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GEOLOGY  OF  CALIFORNIA. 


YOL.  I. 


MOUNT  LYELL  GROUP,  AND  THE  SOURCE  OF  THE  TUOLUMNE  RIYER. 


tIBRARY 
OF  THE 

UNIVERSITY  OF  ILLINOIS 


GEOLOGICAL  SURVEY  OF  CALIFORNIA. 

J.  D.  WHITNEY,  State  Geologist. 


G  E  0  L  0  G  Y 

VOLUME  I. 


Report  of  Progress 

AND 

SYNOPSIS  OF  THE  FIELD-WORK, 


From  1860  to  1864. 


PUBLISHED  BY  AUTHORITY  OF  THE  LEGISLATURE  OF  CALIFORNIA. 

1865. 


CAXTON  PRESS  OE 


SHERMAN  &  CO.,  PHILADELPHIA 


MEMBERS  OF  THE  CORPS 


From  1860  to  1864. 


Professor  J.  D.  Whitney,  ....  State  Geologist. 

Professor  W.  H.  Brewer, . Principal  Assistant,  1860-64,  in  charge 

of  Botanical  Department. 

J.  G.  Cooper,  M.D., . Zoologist,  1860-64. 

W.  Ashburner, . Assistant  in  the  Department  of  Eco¬ 

nomical  Geology,  1860-61. 

C.  F.  Hoffmann, . Principal  Topographical  Assistant, 

1861-64. 

V7.  Wackenreuder, . Topographical  Assistant,  1862,  1863. 

W.  M.  Gabb, . Palseontologist,  1862-64. 

A.  Remond, . Volunteer  Assistant  in  the  Geological 

Field-work,  1862,  1863. 

Clarence  King, . Volunteer  Assistant  in  the  Geological 

Field-work,  1863-64. 

J.  T.  Gardner, . Volunteer  Assistant  in  the  Topograph¬ 

ical  Field-work,  1864. 

C.  Averill, . Clerk,  Commissary  and  Barometrical 

Observer,  1860-63. 


The  Survey  was  instituted  in  April,  1860:  Field-work  commenced, 

November,  1860. 


3)  £>  & 


• 

- 


♦ 


TABLE  OF  CONTENTS 


PREFACE, 


rr  i. 

GEOLOGY  OF  THE  COAST  RANGES. 

CHAPTER  I. — Introductory, . 

CHAPTER  II. — The  Monte  Diablo  Range, . 

Section  1.  Introductory,  .......... 

2.  Contra  Costa  Hills,  ......... 

3.  Monte  Diablo  Group,  ........ 

4. -  Mount  Hamilton  Group,  ........ 

5.  Monte  Diablo  Group,  south  of  Pacheco’s  Pass, 

CHAPTER  III. — The  Peninsula  of  San  Francisco,  including  the  Re¬ 
gion  from  the  Bay  of  Monterey  to  the  Golden 
Gate,  ...  . 

CHAPTER  IV.  —  The  Coast  Ranges  north  of  the  Bay  of  San  Fran¬ 
cisco,  . 

CHAPTER  V. — The  Coast  Ranges  south  of  the  Bay  of  Monterey, 
Section  1.  Introductory  Remarks,  ........ 

2.  The  Region  from  San  Fernando  Valley  north  to  the  Bay  of 

Monterey,  .......... 

3.  The  Gavilan  Range,  ......... 

4.  The  Vicinity  of  the  Bay  of  Monterey,  ..... 
CHAPTER  VI. — The  Coast  Ranges  from  the  vicinity  of  Los  Angeles, 

SOUTH, . 

Section  1.  Preliminary  Remarks,  ........ 

2.  Sierra  Santa  Monica,  ........ 

3.  San  Gabriel  Range  and  the  Vicinity  of  Los  Angeles, 

4.  Santa  Anna  and  Temescal  Ranges,  ...... 

5.  Islands  off  the  Coast  of  Southern  California,  .... 
CHAPTER  VII. — The  Region  between  the  Canada  de  las  Uvas  and 

Soledad  Pass, . 


PAGE 

ix 


1-7 

8-60 

8-11 

11-19 

19-39 

39-52 

52-60 


61-79 

80-108 

108-166 

108-119 

119-158 

159- 160 

160- 166 

166-186 

166-168 

168-171 

171-175 

175-181 

182-186 


186-197 


VI 11 


TABLE  OF  CONTENTS. 


PABT  II. 

THE  GEOLOGY  OF  THE  SIERRA  NEVADA. 

PAGE 

CHAPTER  VIII. — The  Undisturbed  Marine  Sedimentary  Rocks  along 

the  Foot-hills  oe  the  Swrra, . 199-212 

CHAPTER  IX. — The  Mining  Region  of  -California;  embracing  the 

great  Auriferous  Belt  along  the  Western  Slope 


of  the  Sierra  Nevada,  ..... 

• 

212-363 

Section  1. 

Preliminary  Remarks,  ....... 

• 

212-216 

2. 

From  Tejon  Pass  to  Mariposa,  ...... 

■ 

216-222 

3. 

Mariposa  County,  ........ 

• 

223-231 

4. 

Tuolumne  County,  ........ 

• 

232-253 

5. 

Calaveras  County,  ........ 

• 

253-268 

6. 

Amador  County,  ........ 

• 

269-278 

i . 

El  Dorado  County,  ........ 

• 

279-283 

8. 

Placer  County,  ........ 

• 

283-287 

9. 

Nevada  County,  ........ 

• 

287-298 

10. 

Sierra  County,  ........ 

• 

298-304 

11. 

Plumas  County,  ........ 

• 

304-316 

12. 

The  Northern  Counties,  ....... 

• 

316-363 

CHAPTER  X.- 

-The  High  Sierra, . 

• 

364-450 

Section  1. 

Preliminary  Remarks,  ....... 

. 

364-365 

2. 

The  Region  about  the  Head  of  Kern  and  King’s  Rivers, . 

• 

365-391 

3. 

The  Head  of  the  San  Joaquin  River,  .... 

• 

391-403 

4. 

The  Region  about  the  Heads  of  the  Merced  and  Tuolumne 

Rivers, .......... 

• 

403-437 

5. 

The  Sonora  Pass,  ........ 

• 

437-443 

6. 

The  Head  of  the  Mokelumne  River.  The  Road  from 

the 

Calaveras  Big  Trees  to  Silver  Mountain,  . 

. 

443-450 

CHAPTER  XI. 

— The  Eastern  Slope, . 

450-474 

Section  1. 

Mono  Lake  and  its  Vicinity,  ...... 

• 

450-455 

2. 

Owen’s  Valley,  ......... 

• 

455-460 

3. 

The  Great  Basin,  ........ 

• 

461-474 

APPENDIX  A 

. — Tabular  Statement  of  the  Operations  of  the  prin- 

cipal  Quartz  Mills  running  in  California 

IN 

1861.  By  W.  Ashburner, . 

• 

475-476 

APPENDIX  B 

. — Description  of  Fossils  from  the  Auriferous  Slates 

* 

of  California.  By  F.  B.  Meek, 

. 

477-483 

INDEX, 

. 

485-498 

PREFACE. 


The  Geological  Survey  of  California  was  instituted,  in  1860,  by  the 
passage  of  the  following  Act  of  the  Legislature  of  that  State  : 

AN  ACT  TO  CREATE  THE  OFFICE  OF  STATE  GEOLOGIST,  AND  TO 

DEFINE  THE  DUTIES  THEREOF. 

The  People  of  the  State  of  California,  represented  in  Senate  and  Assembly,  do  enact 
as  follows  : 

Section  One.  J.  D.  Whitney  is  hereby  appointed  State  Geologist,  whose  duty  it  shall 
be,  with  the  aid  of  such  assistants  as  he  may  appoint,  to  make  an  accurate  and  complete 
Geological  Survey  of  the  State,  and  to  furnish,  in  his  Report  of  the  same,  proper  maps  and 
diagrams  thereof,  with  a  full  and  scientific  description  of  its  rocks,  fossils,  soils,  and  min¬ 
erals,  and  of  its  botanical  and  zoological  productions^  together  with  specimens  of  the  same, 
which  specimens  shall  be  properly  labelled,  and  arranged  and  deposited  in  suck  place  as 
shall  be  hereafter  provided  for  that  purpose  by  the  Legislature. 

Section  Two.  Said  State  Geologist  shall,  as  near  as  may  be,  at  the  beginning  of  each 
session  of  the  Legislature,  present  to  the  Governor,  who  shall  lay  the  same  before  the 
Legislature,  a  report  of  progress,  in  which  the  operations  of  the  Geological  Survey  during 
the  preceding  year  shall  be  set  forth,  and  its  more  important  practical  results  made  public. 
He  shall  also  furnish  such  estimates  as  he  shall  deem  proper  of  the  amount  of  appropria¬ 
tion  which  shall  be  required  for  the  continuance  of  the  Survey.  His  report  shall  also 
embrace  the  amount  of  expenses  incurred  up  to  that  period. 

Section  Three.  On  the  completion  of  the  Survey,  the  State  Geologist  shall  prepare 
and  present  to  the  Governor  a  full  and  comprehensive  Report,  embodying  the  results  of 
the  entire  Survey,  with  proper  maps,  diagrams,  and  drawings  of  the  same  ;  and  the  Secre¬ 
tary  of  State  is  hereby  directed  to  obtain  the  copyright  for  the  same,  as  also  of  the  annual 
reports  of  said  Geologist,  for  the  benefit  of  this  State. 

Section  Four.  Whenever  one  or  more  volumes  of  the  Geological  Survey  herein  pro¬ 
vided  for  shall  be  published,  the  Governor  and  Secretary  of  State  may  cause  such  books 
to  be  sold  upon  the  most  advantageous  terms  to  the  State;  and  any  moneys  derived  from 
such  sales  shall  be  placed  in  the  Common  School  Fund  of  the  State. 

Section  Five.  The  said  Geologist  shall  prepare  and  superintend  the  publication  of 
his  reports  of  the  final  results  of  the  Survey  provided  for  in  this  act,  and  he  shall  present 
to  the  Legislature  an  estimate  of  the  costs  of  such  publication. 

Section  Six.  The  State  Geologist  shall  receive  for  his  compensation  the  sum  of  six 
thousand  dollars  per  annum,  payable  monthly  ;  and  his  assistants  shall  receive  such  com¬ 
pensation  as  shall  be  determined  upon  by  the  Governor  and  said  Geologist,  which,  together 
with  the  salary  of  the  State  Geologist,  shall  be  audited  by  the  State  Controller,  and  paid 


GKOL.  VOL.  i. — B 


X 


PREFACE. 


out  of  the  amount  herein  appropriated,  or  out  of  such  appropriations  as  shall  be  hereafter 
made  for  that  purpose ;  provided  that  the  compensation  herein  allowed  shall  be  paid  only 
from  the  time  they  shall  enter  upon  the  performance  of  their  duties. 

Section  Seven.  Whenever  the  said  J.  D.  Whitney  shall  notify  the  Governor  of  his 
acceptance  of  the  appointment  herein  made,  the  Governor  shall  cause  to  be  issued  to  said 
Whitney  his  commission  under  the  seal  of  State ;  and  if  the  said  Whitney  shall  decline 
to  serve  as  said  Geologist,  or  die,  or  become  unable  to  prosecute  said  Survey,  the  Governor 
of  this  State  is  hereby  authorized  to  appoint  some  suitable  person  to  prosecute  said  Survey. 

Section  Eight.  The  sum  of  twenty  thousand  dollars  is  hereby  set  apart  out  of  any 
moneys  in  the  State  Treasury,  not  otherwise  appropriated,  as  a  special  fund  for  the  payment 
of  expenses  incurred  by  said  Survey. 

Section  Nine.  This  Act  shall  take  effect  from  and  after  its  passage. 

PHIL.  MOORE, 

Speaker  of  the  Assembly. 

J.  N.  QUINN, 

President  of  the  Senate. 

Approved  April  21,  1860. 

JOHN  G.  DOWNEY, 

Governor. 


At  the  time  my  commission  as  State  Geologist  reached  me  I  was  engaged 
in  making  a  survey  of  the  Lead  Region  of  the  Northwest,  under  authority 
of  the  Legislature  of  Wisconsin.  This  work  was  completed,  and  the  Report 
written,  so  that  I  was  able  to  sail  for  California  on  the  22d  of  the  following: 
October.  Prof.  W.  H.  Brewer  and  Mr.  William  Ashburner  accompanied 
me;  the  former  as  Principal  Assistant,  in  charge  of  the  Botanical  Depart¬ 
ment;  the  latter  as  Assistant  in  the  Geological  Field-work. 

We  landed  at  San  Francisco,  November  14th,  and  proceeded  at  once  to 
organize  our  party  for  the  commencement  of  the  explorations,  which  of 
course  could  only  be  carried  on  in  the  Southern  part  of  the  State  during  the 
winter.  Mr.  C.  Averill  was  engaged  as  clerk,  commissary,  and  barometrical 
observer,  and  we  were  also  accompanied  by  Mr.  F.  Guirado,  who  was  well 
acquainted  with  the  region  we  proposed  visiting.  Our  labors  commenced, 
after  the  completion  of  the  necessary  preparations,  on  the  12th  of  December, 
and  the  party  did  not  return  to  San  Francisco,  where  our  office  was  estab¬ 
lished,  until  the  15th  of  the  next  November,  having  been  uninterruptedly7 
occupied  in  the  field-work  during  a  period  of  nearly  a  year. 

This  first  y7ear  was  almost  exclusively  devoted  to  the  Coast  Ranges.  We 
first  made  a  reconnaissance  of  a  portion  of  Los  Angeles  and  San  Bernardino 
Counties,  then  proceeded  north  through  Santa  Barbara,  San  Luis  Obispo, 
and  Monterey7  Counties,  spending  the  summer  chiefly  in  the  Monte  Diablo 
Range,  then  crossing  over  to  the  north  side  of  the  Bay  of  San  Francisco, 
and  reaching  the  Geysers  just  at  the  commencement  of  the  rainy  season. 
From  the  time  of  our  taking  the  field  up  to  February  7th  I  was  with  the  party 
uninterruptedly";  and  after  that,  at  various  times,  spending  from  a  few  days 
to  several  weeks  with  them,  at  places  of  particular  interest,  or  when  other 
duties  did  not  interfere.  Professor  Brewer  had  charge  of  the  party  at  times 
when  I  was  unable  myself  to  be  with  them. 


P  REFACE. 


XI 


Mr.  Ash  burner  was  detached  from  the  general  field-work  on  the  21st  of 
February,  1861,  and  was  engaged,  from  that  time  up  to  November  20th,  in 
an  examination  of  the  auriferous  quartz  mines  of  the  Sierra  Nevada,  from 
Mariposa  to. Plumas  Counties. 

While  absent  from  the  main  party,  I  spent  a  portion  of  the  time  in  at¬ 
tending  to  the  general  business  of  the  Survey,  a  portion  with  Mr.  Ash- 
burner,  and  the  remainder  in  examining,  by  myself,  certain  districts,  my 
object  being,  during  the  first  year,  to  initiate  my  assistants  into  their  work, 
and  to  obtain  a  general  idea  of  the  geological  structure  of  the  State  over  as 
large  an  extent  of  surface  as  possible,  so  that  I  might  be  enabled  to  lay  my 
plans  for  the  future  conduct  of  the  Survey  with  a  better  understanding  of 
what  there  wras  to  be  done,  and  what  it  was  likely  to  be  in  our  power  to 
accomplish. 

Mr.  C.  F.  Hoffmann  joined  the  corps  as  Topographical  Assistant,  March 
26th,  1861,  and  was  immediately  employed  in  compiling,  at  the  United 
States  Surveyor-General’s  Office,  such  geographical  information  as  could  be 
obtained.  The  Department  of  Zoology  wras  also  organized,  by  the  appoint¬ 
ment  of  Dr.  J.  G.  Cooper  to  the  place  of  Zoologist  to  the  Survey,  July  1st 
of  the  same  year. 

At  the  beginning  of  the  year  1862,  Mr.  W.  M.  Gabb  arrived  in  California, 
having  been  selected  by  me  for  the  post  of  Palaeontologist  to  the  Survey. 
His  duties  w7ere  entered  on  at  once,  by  commencing  with  the  collections  of 
fossils  made  by  us  during  the  previous  year. 

Deferring  the  fitting  up  of  a  laboratory,  and  the  engaging  of  a  special 
assistant  in  the  chemical  department,  until  a  suitable  permanent  place 
could  be  provided  in  the  State  Museum  building,  I  sent  Mr.  Ashburner  east 
in  the  spring,  to  commence  the  examination  of  some  of  the  ores  and 
minerals  of  the  State  in  the  laboratory  of  the  Sheffield  Scientific  School  of 
Yale  College,  under  the  direction  of  Professor  Brush,  who  has  charge  of  the 
metallurgical  department  of  that  institution.  The  reduction  of  the  appro¬ 
priation  to  $15,000  for  the  next  year  made  it  necessary  to  suspend  this 
work  soon  after  it  wras  commenced,  in  order  that  the  whole  force  of  the 
Survey  might  be  concentrated  on  the  field  operations,  and  Mr.  Ash  burner’s 
connection  with  the  Survey  was  terminated. 

In  1862,  the  field-work  was  much  delayed  in  its  commencement  by  the 
almost  entire  destruction  of  the  roads  and  bridges  throughout  the  State, 
consequent  on  the  unprecedented  storms  of  the  preceding  winter.  Our 
wagon  being  at  San  Francisco,  and  our  mules  at  Clayton,  in  Contra  Costa 
County,  we  were  unable  to  commence  operations  with  the  whole  party  until 
the  creek  at  Pacheco  was  made  passable;  this  was  in  the  latter  part  of 
April.  Previous  to  this,  however,  the  geology  and  topography  of  Marin 
and  a  part  of  Sonoma  County  were  worked  up  by  Messrs.  Brewer  and 
Hoffmann,  during  the  months  of  March  and  April. 

The  explorations  of  1861  having  revealed  the  presence  of  Cretaceous 
rocks  in  the  Monte  Diablo  Range,  and  various  circumstances  making  it 


Xll 


PREFACE. 


apparent  that  the  vicinity  of  Monte  Diablo  itself,  by  a  detailed  and  careful 
study,  would  throw  much  light  on  the  structure  of  the  Coast  Ranges,  and 
furnish  a  key  to  what  had  been  previously  more  or  less  obscure  in  the  stra- 
tigraphical  position  of  the  rocks  south  and  west  of  the  San  Joaquin,  I 
determined,  having  especially  in  view  the  economical  importance  of  the 
coal  of  that  region,  to  make  first  a  thorough  examination  of  the  vicinity  of 
the  mountain,  and  a  topographical  map,  on  a  large  scale,  of  the  coal-mining 
district.  This  work  occupied  about  a  month,  during  which  time  I  was  with 
the  party. 

This  accomplished,  the  party,  in  charge  of  Professor  Brewer,  continued 
their  explorations  along  the  east  side  of  the  Monte  Diablo  Range,  as  far  as 
Pacheco’s  Pass,  mapping  an  extensive  district,  of  which  hardly  anything 
had  been  previously  known.  This  occupied  the  month  of  June. 

After  this  was  accomplished,  it  had  been  my  intention  to  have  the  party 
cross  the  San  Joaquin  and  meet  me  at  Snelling’s  on  the  Merced,  and  then 
to  devote  our  wThole  strength,  for  the  remainder  of  the  season,  to  working 
up  the  geology  of  the  foot-hills  of  the  Sierra  Nevada,  going  as  far  north  as 
time  would  permit,  and  then  returning  on  the  wrest  side  of  the  Sacramento, 
in  the  foot-hills  of  the  Coast  Ranges.  It  appeared,  however,  that  all  the 
ferries  of  the  San  Joaquin  had  been  broken  up  by  the  winter’s  storms;  and 
up  to  August,  there  was  no  possibility  of  crossing  at  any  point,  the  river 
continuing  greatly  swmllen  by  the  melting  of  the  snow  of  the  Sierra  until 
late  in  the  season.  This  made  a  great  change  necessary  in  our  plans.  The 
party  had  to  return  up  the  San  Jose  valley,  and  cross  at  Benicia.  I  then 
determined  to  continue  our  surveys  up  the  Sacramento,  along  the  Coast 
Ranges  wTest  of  that  river,  and  to  reach  Mount  Shasta  not  too  late  in  the 
season  to  make  the  ascent,  and,  if  possible,  to  get  some  idea  of  the  geology 
of  the  northern  portion  of  the  State.  The  party  had  proceeded  as  far  as 
Rag  Canon,  and  vTere  about  to  explore  Bereyessa  Yalley,  Avhen  the  severe 
sickness  of  Professor  Brewer  put  a  stop  to  our  operations  in  that  quarter. 
After  his  recovery,  it  became  necessary  to  move  up  the  Sacramento  Yalley 
quite  rapidly  in  order  to  reach  Mount  Shasta  in  season  to  make  the  ascent 
that  year.  At  Shasta  City,  however,  three  of  the  party  wrnre  attacked  by 
fever,  and  another  serious  delay  w7as  occasioned.  I  joined  them  at  that 
place  about  the  first  of  September,  and  leaving  Mr.  Remond  there  to  observe 
the  barometer,  with  the  rest  of  the  party  went  up  the  Upper  Sacramento 
Yalley,  ascended  Mount  Shasta  wfith  Messrs.  Brewrnr  and  Averill,  and 
determined  its  height.  The  party  continued  their  work  in  Shasta,  Siski¬ 
you,  and  Trinity  Counties,  until  October,  although  during  the  whole  time 
some  of  them  were  suffering  more  or  less  from  bilious  attacks. 

During  the  month  of  October,  the  work  was  continued  down  the  east 
side  of  the  Sacramento  Yalley,  for  the  purpose  of  settling  the  relations  of 
the  Cretaceous  strata  of  that  region  to  the  auriferous  slates  of  the  Sierra 
Nevada.  Near  the  end  of  the  month  the  party  was  broken  up,  and  the 
animals  sent  into  winter  quarters,  the  explorations  being  continued  in  the 


PREFACE. 


Xlll 


counties  adjacent  to  the  Bay  of  San  Francisco,  by  small  parties  on  foot,  or 
by  single  individuals,  in  different  sections,  to  gain  additional  topographical 
and  geological  information  for  our  map  of  that  region.  These  explorations 
occupied  the  whole  of  the  month  of  November,  during  which  the  weather 
continued  highly  favorable.  During  this  season,  Messrs.  Brewer,  Hoff¬ 
mann,  Gabb,  Averill,  and  Remond  participated  in  the  field-work,  the  last- 
named  gentleman  rendering:  efficient  service  as  a  volunteer  in  the  Geolog;- 
ical  Department  for  several  months. 

In  18C3  the  field-work  was  commenced,  on  the  1st  of  April,  by  a  visit  of 
Messrs.  Brewer  and  Gabb  to  the  region  about  Fort  Tejon  and  the  Canada  de  • 
las  Uvas.  After  a  month  spent  in  that  portion  of  the  State,  they  travelled 
up  the  east  side  of  the  San  Joaquin  to  Mariposa  County,  from  which  point 
Mr.  Gabb  returned  to  San  Francisco,  to  go  on  with  the  palaeontological  work 
at  the  office.  Mr.  Hoffmann  and  I  then  joined  Professor  Brewer,  and  we 
together  made  an  examination  of  the  High  Sierra  at  the  head  of  the  Mer¬ 
ced  and  Tuolumne  Rivers.  The  months  of  June, .July,  and  a  part  of  August, 
were  occupied  in  exploring  the  mountains  between  the  Mono  Pass  and  the 
Silver  Mountain  district,  Mr  Hoffman,  however,  returning  to  San  Francisco 
and  resuming  his  office-work  before  the  end  of  July.  The  rest  of  the  season 
was  spent  by  Professor  Brewer,  accompanied  by  Mr.  Clarence  King  as  a 
volunteer  assistant,  in  continuing  the  reconnaissance  of  the  High  Sierra  to 
the  north.  Working  along  the  most  elevated  portion  of  the  range,  and  cross¬ 
ing  over  nearly  all  the  important  passes,  they  made  their  way  around  the 
eastern  side  of  Mount  Shasta,  examined  the  vicinity  of  Yreka,  and  finally 
came  down  to  Crescent  City,  late  in  November.  From  this  place,  Professor 
Brewer  returned  to  San  Francisco  by  boat,  and  Mr.  King  by  stage.  During 
the  time  that  this  small  party  was  thus  engaged,  I  was  employed  in  exam¬ 
ining  the  geology  of  the  lower  portion  of  the  western  slope  of  the  Sierra, 
in  the  region  of  the  most  important  mines. 

Up  to  this  time  the  following  sums  had  been  appropriated  for  the  con¬ 
tinuance  of  the  Survey  : 


At  the  time  of  the  passage  of  the  Act, 
By  the  Legislature  of  1860-1, 

By  the  Legislature  of  1861-2, 

By  the  Legislature  of  1862-3, 


$20,000 

15,000 

15,000 

20,000 


Making  in  all, 


$70,000 


Besides  this,  $3000  was  appropriated  by  the  Legislature  of  1861-2  for 
printing  one  volume  of  the  Report. 

As,  by  the  Constitution  of  the  State,  no  office  can  be  created  by  the  Legis¬ 
lature  which  shall  last  over  four  years,  and  as,  under  this  provision,  the 
office  of  State  Geologist  would  cease  to  exist  in  April,  1864,  of  course  a  dis¬ 
continuance  of  the  Survey  at  that  time  would  be  inevitable,  unless  a  new 
Act  should  be  passed.  It  will  be  noticed,  however,  that  the  Survey  had,  at 


XIV 


PREFACE. 


the  beginning  of  the  winter  of  1863-4,  been  going  on  only  three  years,  owing 
to  the  necessary  delay  in  commencing  the  work. 

At  the  time  the  Legislature  of  1863-4  met,  the  new  Constitution  of  the 
State  was  in  operation,  and  the  sessions  being  now  biennial,  instead  of 
annual,  it  was  necessary  to  provide  funds  for  continuing  the  Survey  for  two 
years.  Unfortunately,  the  State  was  at  this  time  in  great  trouble,  the 
drouth  of  the  two  previous  winters  having  most  seriously  affected  both  the 
agricultural  and  the  mining  interests,  and  given  rise  to  a  wide-spread  feel¬ 
ing  of  alarm.  It  was  with  difficulty  that  any  appropriation  could  be  secured 
for  the  Survey,  especially  as  it  was  necessary  that  an  act  should  be  passed 
creating  the  office  of  State  Geologist  anew.  This  was,  however,  accom¬ 
plished,  and  the  following  enactment  became  a  law  : 

AX  ACT  TO  CREATE  THE  OFFICE  OF  STATE  GEOLOGIST,  AND  TO 

DEFINE  THE  DUTIES  THEREOF. 

The  People  of  the  State  of  California,  represented  in  Senate  and  Assembly,  do  enact  as 
follows : 

Section  One.  J.  D.  Whitney  is  hereby  appointed  State  Geologist.  He  shall  be  com¬ 
missioned  by  the  Governor,  and  it  shall  be  his  duty,  with  the  aid  of  such  assistants  as  he 
may  appoint,  to  complete  the  Geological  Survey  of  the  State,  and  prepare  a  Report  of  said 
Survey  for  publication,  and  superintend  the  publication  of  the  same.  Such  Report  shall 
be  in  the  form  of  a  geological,  botanical,  and  zoological  history  of  the  State,  and  the 
number  of  volumes,  and  the  number  of  copies  of  each  volume  to  be  printed,  and  the 
style,  form,  maps,  diagrams  or  illustrations  to  be  contained  therein,  or  to  be  published 
separately,  shall  be  determined  by  the  State  Geologist,  and  said  Report,  when  published, 
shall  be  sold  upon  such  terms  as  the  Governor  and  Secretary  of  State  may  decide  upon, 
and  the  proceeds  of  such  sales  shall  be  paid  into  the  Common  School  Fund  of  the  State. 

Section  Two.  It  is  hereby  made  the  duty  of  the  State  Geologist  and  his  assistants,  to 
devote  the  time  not  necessarily  required  in  the  preparation  and  superintendence  for  pub¬ 
lication  of  the  Reports  provided  for  in  Section  One  of  this  Act,  to  a  thorough  and  scientific 
examination  of  the  gold,  silver,  and  copper  producing  districts  of  this  State,  and  to  make 
such  scientific  and  practical  experiments  as  will  be  of  value  in  the  discovery  of  mines 
and  the  working  and  reduction  of  ores. 

Section  Three.  The  following  sums  of  money  are  hereby  appropriated,  out  of  any 
money  in  the  State  Treasury  not  otherwise  appropriated,  for  the  prosecution  of  the  Geo¬ 
logical  Survey  of  the  State,  and  for  the  sixteenth  and  seventeenth  fiscal  years:  For  salary 
of  the  State  Geologist,  nine  thousand  dollars ;  to  be  drawn  monthly  on  the  last  day  of 
each  month.  For  salary  of  two  assistants,  six  thousand  six  hundred  dollars  ;  to  be  drawn 
in  the  same  manner  as  the  salary  of  the  State  Geologist.  For  publication  of  two  vol¬ 
umes  of  Report,  six  thousand  dollars.  For  office  rent  and  expenses  of  Survey  in  mining 
districts,  and  experiments  on  ores  and  all  incidental  expenses  of  work,  ten  thousand  dol¬ 
lars  ;  to  be  drawn  one-half  each  fiscal  year. 

Section  Four.  This  Act  shall  take  effect  immediately. 

R.  BURNELL, 

President  of  the  Senate,  pro  tem. 

WM.  II.  SEARS, 

Speaker  of  the  Assembly. 

Approved,  April  4,  1864. 

FREDERICK  F.  LOW, 

Governor. 


PREFACE. 


XV 


The  appropriation  for  the  Survey  in  the  above  Act,  added  to  those  of  pre¬ 
vious  Legislatures,  make  the  total  amount  provided  for  the  field-work  and 
salaries  in  all  departments,  from  the  commencement  of  the  Survey  up  to 
June  30,  18G6,  895,600,  or  a  little  less  than  $16,000  a  year,  on  the  average. 
Besides  this,  there  has  been  $9000  appropriated  for  publication;  which, 
however,  should  not  be  debited  to  the  Survey,  as  this  amount  will  be  re¬ 
funded  to  the  State  by  the  sale  of  the  volumes  published,  it  being  provided, 
in  both  Acts,  that  our  publications  shall  be  sold,  and  the  money  paid  into  the 
Common  School  Fund. 

Since  the  passage  of  the  new  Act,  by  which  only  $12,300  a  year  were 
appropriated  for  the  Survey,  our  field  operations  have  necessarily  been  very 
much  cut  down,  most  of  our  time  and  money  having  been  absorbed  in  the 
preparation  and  publication  of  portions  of  our  results.  The  field-work  done 
has  all  been  in  the  Sierra  Nevada,  in  accordance  with  the  provisions  of  the 
Act  reconstituting  the  Survey. 

In  1864,  a  small  party,  consisting  of  Messrs.  Brewer  and  Hoffmann, 
accompanied  by  Messrs.  King  and  Gardner  as  volunteer  assistants,  com¬ 
menced  operations  in  the  southern  portion  of  the  Sierra,  it  being  my  inten¬ 
tion  to  work  up  the  geology  and  topography  of  that  great  chain,  from  the 
south  towards  the  north,  as  thoroughly  and  accurately  as  our  means  should 
permit.  The  interesting  results  obtained  by  the  party  will  be  found  in  Sec¬ 
tions  2  and  3  of  Chapter  X  of  this  volume. 

In  May,  of  the  same  year,  I  left  California  for  the  East,  to  commence  the 
publication  of  a  portion  of  our  results  in  the  different  departments,  agree¬ 
ably  to  the  provisions  of  the  Act,  and  in  accordance  with  my  understanding 
with  the  “Committee  on  Mines  and  Mining  Interests”  of  the  Legislature. 
What  progress  has  been  made  in  the  publication,  up  to  the  present  time, 
will  be  specified  under  the  appropriate  heads,  farther  on  in  this  Preface,  in 
connection  with  a  statement  of  the  amount  of  work  accomplished  by  the 
Survey  in  each  department. 

At  the  end  of  the  campaign  of  1864,  Professor  Brewer  relinquished  his 
position  as  Principal  Assistant,  leaving  California  to  enter  on  his  duties  as 
Professor  in  the  Sheffield  Scientific  School  of  Yale  College.  He  still  re- 
mains,  however,  charged  with  the  Botanical  Department  of  the  Survey,  as 
will  be  noticed  farther  on  under  the  head  of  Botany. 

During  the  year  1865,  Mr.  Gabb  has  been  employed  for  a  portion  of  the 
time  in  completing  the  revision  of  our  palaeontological  materials,  and  Mr. 
Hoffmann  in  compiling  our  geographical  materials  relating  to  the  central 
portion  of  the  State.  Field-work  has  been  carried  on — not  on  a  large  scale, 
as  it  is  hardly  necessary  to  add — by  Mr.  Eemond,  who  is  now  connected 
with  the  Survey  as  Geological  Assistant,  and  who  has  been  employed  in 
continuing  the  detailed  explorations  of  the  mining  region  of  the  Sierra,  from 
the  south  towards  the  north,  in  accordance  with  the  plan  of  operations  indi¬ 
cated  above. 

Having  thus  given  a  brief  sketch  of  the  progress  of  the  field-work  of  the 


XVI 


PREFACE. 


Survey,  in  connection  with  the  notice  of  the  action  of  the  Legislature  at 
various  times,  it  remains  to  add  a  statement  of  what  has  been  accomplished 
in  each  department  of  our  work,  with  especial  reference  to  the  preparation 
and  publication  of  the  “  geological,  botanical,  and  zoological  history  of  the 
State,' ”  provided  for  by  the  last  Legislature. 


1.  Topography. 

Recognizing  most  distinctly,  from  the  first,  the  great  importance  to  the 
State  of  the  topographical  work  of  our  Survey,  and  the  absolute  necessity 
of  maps  at  least  approximately  correct,  if  we  would  do  anything  satisfac¬ 
tory  in  the  Geological  Department,  I  have  done  all  that  was  possible — and 
sometimes  more  than  the  Legislature  has  provided  the  means  for — towards 
the  increase  of  our  geographical  knowledge  of  the  vast  area  comprised 
within  the  boundaries  of  California,  It  is  not  necessary,  at  this  time,  to  go 
into  a  minute  account  of  our  operations  in  this  department  of  the  Survey; 
it  need  only  be  briefly  stated  that  at  the  time  our  work  wTas  commenced 
nothing  was  accurately,  and  very  little  even  approximately,  known  in 
regard  to  the  topography  of  the  mountainous  regions  of  the  State;  and, 
when  we  consider  that  the  plains  and  broad  valleys  do  not  together  occupy 
more  than  one-fifteenth  of  its  area,  it  will  be  evident  that  the  task  before  us 
was  truly  one  of  no  common  magnitude.  The  surveys  made  under  au¬ 
thority  of  the  United  States  by  the  General  Land  Office  are  never  carried 
into  the  mountains;  their  lines  stop  at  the  base  of  the  hills,  except  where 
there  are  only  very  moderate  elevations.  This  is  true  even  for  the  Coast 
Ranges;  and,  in  the  Sierra  Nevada,  the  United  States  linear  surveyors  have 
done  no  work  worthy  of  notice.  In  short,  there  was  not  a  map  of  any  por¬ 
tion  of  the  State  sufficiently  correct  in  its  details  to  allow  of  our  laying  down 
even  the  outlines  of  the  geology  upon  it. 

In  commencing  our  topographical  work,  we  first  compiled  at  the  LTnited 
States  Surveyor-General’s  Office,  at  San  Francisco,  all  the  geographical 
information  which  could  be  obtained,  on  a  series  of  over  fifty  skeleton  maps, 
on  a  scale  of  half  an  inch  to  the  mile;  these  have  been  used  by  us  in  the 
field,  especially  in  the  Coast  Ranges  and  along  the  edge  of  the  foot-hills  of 
the  Sierra,  and  we  have  sketched  in  the  topography  upon  them,  whenever 
we  explored  the  regions  which  they  covered.  In  the  elevated  portion  of 
the  Sierra  Nevada  we  have  done  work  enough  to  enable  us  to  give  a  gen¬ 
eral  idea  of  the  topography  of  the  great  chain  from  Walker’s  Pass  north  to 
Mount  Shasta,  with  the  exception  of  a  few  blanks,  the  most  important  of 
which  is  the  region  between  the  Henness  Pass  and  Lassen’s  Peak.  A  hasty 
reconnaissance  has  been  made  of  that  part  of  the  Sierra  w^hich  lies  between 
the  parallels  of  36°  and  37°  30',  comprising  an  area  of  over  10,000  square 
miles,  of  which  not  even  the  outlines  of  the  topography  were  known  pre¬ 
vious  to  our  visit.  The  exploration  of  this  region  disclosed  the  interesting 


PREFACE. 


XVII 


fact  that  the  highest  mountains  of  the  State  are  included  within  it,  as  well 
as  the  grandest  scenery. 

Mr.  Waekenreuder  has  also  been  employed  by  us  during  portions  of  two 
seasons  in  surveying  the  High  Sierra  between  Silver  Mountain  and  the 
Downieville  Buttes.  His  map,  four  and  a  half  feet  by  four  in  size,  contains 
a  large  amount  of  original  information,  obtained  by  the  most  arduous  and 
persevering  exertions. 

The  following  maps  have  been  prepared  for  publication  or  are  in  progress  : 

1st.  A  map  of  the  vicinity  of  the  Bay  of  San  Francisco,  on  a  scale  of  half 
an  inch  to  the  mile,  and  four  feet  by  three  in  dimensions.  It  extends  from 
near  Santa  Cruz  on  the  south  to  Napa  on  the  north,  and  from  the  Pacific  to 
Corral  Hollow  east  and  west,  and  covers  an  area  of  four  thousand  two  hun¬ 
dred  and  forty-eight  square  miles  of  land,  which  is  just  twice  that  of  the 
State  of  Delaware,  and  only  lacks  two  hundred  square  miles  of  equalling 
that  of  Connecticut-.  It  embraces,  a  region  far  more  densely  inhabited  and 
thriving  than  any  other  district  of  equal  size  within  the  borders  of  the 
State.  As  near  as  could  be  ascertained  from  the  census  of  1860,  the  district 
included  on  this  map  contains  over  one-third  of  the  population  of  California, 
and  a  considerably  larger  proportion  of  its  wealth.  This  map  has  all  the 
topography  correctly  represented  on  it,  in  as  much  detail  as  the  scale  will 
allow.  It  is  now  ready  for  the  engraver,  and  we  only  await  the  necessary 
appropriation  for  that  purpose  to  have  it  put  in  hand.  It  will  either  be 
colored,  so  as  to  represent  the  range  and  extent  of  the  different  geological 
formations;  or  else  an  outline,  on  a  reduced  scale,  will  be  used  for  this  pur¬ 
pose. 

2d.  A  detailed  topographical  map,  on  a  scale  of  two  inches  to  the  mile,  of 
the  vicinity  of  Monte  Diablo :  this  is  about  two  and  a  half  by  three  feet  in 
dimensions,  and  includes  the  most  important  coal  mines  yet  known  to  exist 
in  the  State.  It  is  now  ready  for  publication,  and  it  is  my  intention  to  have 
it  reproduced  by  the  photolithographic  process,  which,  there  is  reason  to 
believe,  will  soon  be  in  successful  operation  in  this  country. 

3d.  A  map  of  the  Coast  Ranges,  from  the  Bay  of  Monterey  south  to  Santa 
Barbara :  this  is  about  three  feet  by  two  and  a  half  in  dimensions,  and  is 
on  a  scale  of  six  miles  to  the  inch.  It  embraces  about  sixteen  thousand 
square  miles  of  territory,  chiefly  within  the  counties  of  Monterey,  San  Luis 
Obispo,  and  Santa  Barbara.  Considerable  more  field-work  will  be  required 
to  complete  this  map. 

4th.  A  map  of  the  vicinity  of  Virginia  City,  three  and  a  half  by  two  and 
a  half  feet  in  size,  and  on  a  scale  of  two  inches  to  the  mile,  has  been 
drawn  by  Mr.  Waekenreuder  from  his  own  accurate  topographical  surveys. 
This  was  intended  to  form  one  of  our  series  of  map  publications ;  but 
its  cost  has  been  refunded  to  the  State,  and  I  have  placed  it  at  the  disposi¬ 
tion  of  Baron  Richthofen,  the  eminent  geologist,  who  has  been  engaged  for 
some  time  in  making  a  detailed  survey  of  the  region  which  it  covers,  the 
results  of  which  will  be  of  the  greatest  value. 


GEOL.  VOL.  i. — c 


XV111 


PREFACE. 


5th.  A  map  of  the  Comstock  lode  was  prepared  from  the  joint  surveys  of 
Mr.  Wackenreuder  and  myself;  but  this  will  be  superseded  by  the  more 
accurate  and  detailed  one  of  Baron  .Richthofen. 

6th.  A  map  of  Central  California  has  been  for  some  time  in  progress  at 
the  office  of  the  Survey;  it  embraces  the  region  between  the  parallels  of 
36°  and  40°  30',  and  extends  from  the  118th  to  the  123d  meridian  :  this 
includes  the  whole  Sierra  from  Owen’s  Lake  north  to  Lassen’s  Peak,  the 
Washoe  mining  region,  and  the  Coast  Ranges  from  Clear  Lake  on  the  north 
to  Point  Sur  and  New  Idria  on  the  south.  This  will  be  a  highly  valuable 
map,  but  at  least  two  years  more  of  field-work  are  required  to  collect  the 
materials  necessary  for  its  completion. 

All  the  above  maps  were  drawn  by  Mr.  Hoffmann,  when  not  otherwise 
specified. 

The  preparation  of  a  map  of  the  whole  State,  on  a  scale  of  ten  or  twelve 
miles  to  the  inch,  is  one  of  the  objects  we  have  had  in  view  from  the  com¬ 
mencement  of  the  Survey.  Whether  this  desirable  crowning  of  our  topo¬ 
graphical  labors  will  ever  be  reached,  it  is  of  course  impossible  to  say. 

Small,  detailed  maps,  of  particularly  interesting  districts,  will  be  furnished 
as  the  Survey  progresses.  One  of  the  environs  of  San  Francisco,  and  an¬ 
other  of  Monterey  and  its  vicinity,  are  in  preparation.  The  more  important 
mining  districts  will  also  be  illustrated  by  special  maps,  provided  this  is  in 
our  power. 

In  regard  to  our  methods  and  the  relative  degrees  of  accuracy  of  the  dif¬ 
ferent  parts  of  our  topographical  work,  it  is  not  necessary  to  go  into  detail 
at  the  present  time.  It  is  sufficient  to  remark,  that  our  results  in  this,  as 
well  as  all  other  branches  of  the  Survey,  are  necessarily  proportioned  to  the 
means  at  our  command.  We  are  extremely  desirous  of  making  our  work 
as  accurate  as  possible,  but  are  also  of  opinion  that  an  approximation  to  the 
truth  is  better  than  no  knowledge  at  all.  Hence  we  have  drawn  on  all  the 
sources  accessible  to  us  for  information  in  regard  to  the  geography  of  dis¬ 
tricts  we  have  not  ourselves  been  able  to  visit,  and  all  our  authorities  will 
receive  due  credit  whenever  any  of  our  geographical  materials  are  pub¬ 
lished. 


2.  Physical  Geography. 

It  is  intended  to  devote  a  separate  volume  of  the  Report  to  this  subject, 
and  we  have  been  constantly  collecting  materials  in  this  department.  The 
barometrical  measurement  of  heights  among  the  numerous  mountain  ranges 
of  the  State  has  received  especial  attention,  and  the  results  of  a  thorough 
working  over  of  our  hypsometrical  data  will  form  one  of  the  most  important 
chapters  in  this  volume  of  our  publications.  In  this  Connection  we  await 
with  much  interest  the  appearance  of  the  report  of  Major  Williamson  to  the 
Topographical  Bureau  of  the  United  States,  of  his  investigations  into  the 
subject  of  the  laws  governing  the  fluctuations  of  the  barometer  on  the 


PREFACE. 


XIX 


Pacific  coast.  This  work  will  be  of  great  importance  to  science,  and  of 
especial  value  to  us,  as  enabling  us  to  use  our  own  observations  more  intel¬ 
ligently  than  would  be  possible,  unless  we  had  the  means  of  carrying  on  a 
series  of  investigations  similar  to  those  of  Major  Williamson,  and  on  which 
a  great  amount  of  time  and  labor  would  have  to  be  expended.  The  subject 
of  the  distribution  of  the  forest  vegetation  in  the  State  will  occupy  a  chapter 
in  our  volume  of  Physical  Geography;  and  it  is  hoped  that  we  shall  be  able 
to  illustrate  it  with  a  map  showing  the  range  of  the  different  groups  of 
species. 


3.  General  Geology  and  Palaeontology. 

The  present  volume,  which  is  chiefly  devoted  to  a  synopsis  of  our  geolog¬ 
ical  field-work,  will  be  a  sufficient  exhibit  of  our  progress  in  the  investiga¬ 
tion  of  the  geological  structure  of  the  State. 

It  is  to  the  department  of  General  Geology  that,  up  to  the  present  time, 
by  far  the  greater  portion  of  our  attention  has  been  given,  since  the  first 
thing  required  in  a  geological  survey  is  a  knowledge  of  the  general  geolog¬ 
ical  structure  of  the  State,  the  age  of  the  various  formations  which  occur  in 
it,  and  their  range  and  extent,  or  the  position  which  they  occupy  on  the 
surface,  and  their  relations  to  each  other.  Each  group  of  strata,  thus  deter¬ 
mined  by  its  lithological  peculiarities  and  by  the  fossils  which  it  contains, 
is  then  to  be  laid  down  upon  the  map,  in  the  position  which  its  outcrop 
occupies  on  the  surface.  The  general  character  of  the  minerals  and  ores 
which  occur  in  each  formation  or  group  of  strata  having  been  thus  deter¬ 
mined,  the  details  of  their  mode  of  occurrence,  their  relative  abundance, 
and  the  facilities  which  may  exist  in  each  separate  district  for  making  them 
economically  available  must,  after  the  preliminary  general  work  has  been 
done,  be  the  object  of  more  special  and  detailed  examinations.  It  is  not, 
however,  the  business  of  a  geological  surveying  corps  to  act,  to  any  con¬ 
siderable  extent,  as  a  prospecting  party ;  to  do  this  would  require  that  we 
should  confine  our  operations  to  a  very  limited  area ;  the  labors  of  the 
whole  corps  for  an  entire  season  would  not  suffice  to  thoroughly  prospect 
more  than  a  few  hundred  square  miles  in  a  very  rich  mineral  region,  and 
we  should  have  often  to  engage  in  expensive  mining  operations  to  decide 
what  was  really  of  permanent  value.  It  is  our  task,  rather,  to  limit  the 
field  of  research,  and  to  show  to  others  where  their  labors  will  be  best 
bestowed,  preventing  foolish  expenditures  of  time  and  money  in  searching 
for  what  our  general  geological  investigations  have  determined  not  to  exist 
in  sufficient  quantity,  in  certain  formations,  to  be  worth  working.  Espe¬ 
cially  in  the  first  years  of  our  work,  in  a  State  of  such  an  immense  area  as 
California,  our  labors  have  more  the  character  of  a  geological  reconnais¬ 
sance  than  of  a  detailed  survey. 

In  the  department  of  Palaeontology,  one  volume  has  already  been  pub¬ 
lished.  This  contains  in  the  first  section  a  description  of  the  Carboniferous 


XX 


PREFACE. 


fossils  of  Bass’s  Ranch;  the  only  locality  where  any  well-preserved  organic 
remains  of  that  age  have  been  found  within  the  State.  The  second  section 
is  devoted  to  the  fossils  of  the  Triassic  rocks,  including  all  which  have  thus 
far  been  discovered  in  California  and  on  its  borders.  While  we  have  abun¬ 
dant  evidence  that  a  formation  equivalent  in  geological  age  to  the  Alpine 
Trias,  or  the  beds  of  Hallstadt  and  St.  Cassian,  occurs  over  a  vast  area,  and 
forms  an  important  part  of  the  metalliferous  belt  of  the  Pacific  coast,  on 
both  sides  of  the  Sierra,  and  while  fossils  of  this  age  have  been  found  at 
several  localities  within  the  borders  of  California,  our  most  ample  supply  of 
well-preserved  specimens  has  come  from  the  Humboldt  Mining  District,  in 
Nevada.  Hence  we  have  included  in  our  description  of  the  Triassic  fossils 
those  of  that  region,  although  some  among  them  have  not  yet  been  found 
in  California. 

The  third  section  of  the  volume  of  Palaeontology  is  devoted  to  the  Juras¬ 
sic  fossils  of  the  Sierra  Nevada;  or,  rather,  to  such  as  had  been  discovered 
at  the  time  of  its  publication.  These  fossils  are  all  from  the  localities  in 
Genesee  Yalley,  noticed  in  Section  11,  Chapter  IX,  of  this  volume.  At  the 
end  of  this  volume  (Appendix  B.)  a  paper  will  be  found  containing  descrip¬ 
tions  of  the  Jurassic  fossils  of  the  auriferous  slates  in  Mariposa  County, 
from  the  localities  discovered  by  Mr.  King,  and  in  close  proximity  to  one 
of  the  great  quartz  veins  of  the  mining  region  proper.  This  paper  by  Mr. 
Meek,  which  is  also  illustrated  by  a  steel  plate  (Plate  1),  is  published  in  this 
volume,  to  prevent  delay,  as  the  question  of  the  geological  age  of  the  aurif¬ 
erous  slates  is  one  of  great  interest,  and  as  some  time  will  necessarily 
elapse  before  the  second  volume  of  the  Palaeontology  will  be  ready  for  pub¬ 
lication. 

The  fourth  section  is  devoted  to  the  Cretaceous  fossils,  and  forms  con¬ 
siderably  the  larger  portion  of  the  volume,  as  the  rocks  of  this  geological 
age  occupy  a  very  extensive  area  on  the  Pacific  coast,  and  are  rich  in  fos¬ 
sils  at  many  localities.  A  reference  to  the  section  in  question  will  show 
how  large  an  amount  of  material  new  to  science  has  been  derived  from  this 
series,  the  existence  of  which  in  California  had,  previous  to  the  commence¬ 
ment  of  our  work,  been  only  surmised. 

The  first  and  third  sections  of  the  volume  have  been  prepared  by  Mr. 
Meek;  the  second  and  fourth  by  Mr.  Gabb.  The  plates  are  thirty-two  in 
number,  partly  engraved  on  steel  and  partly  on  stone,  from  drawings  fur¬ 
nished  by  the  authors  of  the  text. 

Another  volume  of  the  Paleontology  is  now  partly  ready  for  the  press. 
It  will  be  devoted  chiefly  to  the  fossils,  both  animal  and  vegetable,  of  the 
Tertiary  rocks  of  the  Pacific  coast.  It  will  also  contain  such  additions  to 
our  knowledge  of  the  paleontology  of  the  lower  members  of  the  series  as 
we  may  have  been  able  to  accumulate  since  the  preparation  of  the  first  vol¬ 
ume  was  completed.  For  this,  the  Tertiary  mollusca  have  already  been 
worked  up  by  Mr.  Gabb,  and  the  figures  for  ten  or  twelve  plates  are  drawn. 
The  vertebrate  remains  have  been  referred  to  Dr.  Leidy,  who  has  made  a 


PREFACE; 


XXI 


preliminary  report  on  them,  and  will  prepare  a  more  elaborate  one  on  those 
already  collected  and  such  as  we  may  hereafter  be  able  to  add,  for  the 
second  volume  of  the  Palaeontology.  The  plants  will  be  worked  up  by  Dr. 
Newberry,  and  the  diatoms  and  other  microscopic  forms  have  been  sub¬ 
mitted  to  Mr.  A.  M.  Edwards,  of  New  York.  The  engraving  of  the  plates 
for  this  volume  can  be  commenced  as  soon  as  provision  has  been  made 
therefor  by  the  Legislature. 


4.  Economical  Geology,  Mining,  and  Metallurgy. 

In  the  present  volume  a  considerable  amount  of  information  will  be  found 
in  regard  to  the  economical  geology  of  the  State;  but  all  the  detailed 
descriptions  of  mining  regions  and  mining  processes  have  been  reserved  for 
the  volume  of  the  Report  especially  devoted  to  these  subjects.  We  have  now 
arrived  at  a  stage  of  the  Survey  when,  the  preliminary  reconnaissance  of 
the  State  being  well  advanced,  we  can  take  up  the  mining  districts  and 
work  up  the  details  of  their  geology,  investigate  the  quality,  quantity,  and 
mode  of  occurrence  of  their  ores. 

We  need,  however,  a  laboratory,  where  the  necessary  chemical  work  of 
this  and  other  branches  of  the  Survey  can  be  done  under  my  immediate 
personal  supervision.  Mr.  Ashburner’s  investigations  of  the  quartz  mines 
and  mills  of  the  State  were  the  commencement  of  work  in  this  department ; 
and,  as  far  as  they  go,  they  form  an  important  contribution  to  an  under¬ 
standing  of  the  mining  interests  of  the  State.  The  tabular  statements  pre¬ 
pared  by  him,  to  show  the  principal  facts  connected  with  the  auriferous 
quartz  mills  running  in  1861,  will  always  be  valuable  for  reference.  It  has 
been  given  in  this  volume  (Appendix  A.),  as  that  devoted  to  Economical 
Geology,  Mining,  and  Metallurgy  may  be  long  delayed,  or,  possibly,  entirely 
fail  of  publication. 

The  work  of  investigating,  in  detail,  the  geology  of  the  mining  region  of 
the  State  has  been  begun,  but  will  require  some  }Tears  for  its  completion,  so 
vast  is  the  field  and  so  important  are  the  interests  with  which  this  branch 
of  our  work  is  connected.  We  can  do  much  for  the  benefit  of  the  people  in 
this  direction,  if  properly  supported  by  the  Legislature;  but  hasty  and 
superficial  work  will  be  of  little  use.  Too  large  a  portion  of  the  resources 
of  California  has  already  been  thrown  away  in  foolish  mining  enterprises, 
and  it  is  fully  time  that  a  stop  should  be  put  to  a  course  which  has  already 
materially  retarded  the  progress  of  the  State,  and  which,  if  persisted  in,  will 
bring  utter  financial  ruin  upon  the  people. 

5.  Botany. 

The  Botanical  Department  of  the  Survey  has  been,  and  still  continues, 
under  the  charge  of  Professor  Brewer.  From  his  investigations,  it  appears 


XXII 


PREFACE. 


that  about  1600  species  of  flowering  plants  (including  the  higher  orders  of 
the  flowerless),  and  100  species  of  mosses,  have  been  found  growing  natu¬ 
rally  within  the  limits  of  the  State,  or  on  its  immediate  borders.  In  the 
orders  below  the  mosses  in  the  scale  of  organization,  the  data  are  still  too 
imperfect  to  allow  a  probable  estimate  to  be  made  of  the  number  of  species. 

The  collections  made  by  the  Survey  contain  about  seventy-four  per  cent, 
of  all  the  species  known  to  exist  in  this  State.  About  five  per  cent,  of  them 
are  new  to  science,  and  eleven  per  cent,  new  to  the  State;  that  is,  not  before 
found  within  its  borders. 

Professor  Brewer  is  now  engaged  in  preparing  a  report}  which  will  be,  in 
fact,  a  “  Manual  of  the  Botany  of  California/’  with  as  full  descriptions 
of  all  the  plants  of  the  State  as  can  be  given  in  one  volume;  of  this  the 
general  plan  and  arrangement  will  be  similar  to  those  of  the  “  Colonial 
Floras”  issued  under  the  auspices  of  the  British  Government.  Full  refer¬ 
ences  and  synonyms  will  be  given  of  all  the  species  peculiar  to  the  Pacific 
States  and  which  occur  in  California,  and  a  chapter  will  be  added  on  the 
general  distribution  of  the  plants  of  the  State  and  their  economical  valfie. 
This  volume  will  form  a  suitable  text-book  to  be  used  in  the  schools  of 
the  Pacific  coast,  in  connection  with  “  Gray’s  Lessons  in  Botany,”  or  some 
other  work  of  a  similar  character;  and  it  may  be  added  that  this  science 
cannot  be  taught  in  California  until  such  a  manual  as  the  one  proposed  has 
been  prepared,  since  the  descriptions  of  the  plants  of  the  State  are,  at  present, 
scattered  through  hundreds  of  volumes,  most  of  which  are  quite  inaccessible 
to  any  except  the  few  who  are  furnished  with  costly  and  extensive  botanical 
libraries. 

In  preparing  this  volume — a  task  in  which  considerable  progress  has  been 
made  by  Professor  Brewer — he  will  have  the  aid  of  several  of  the  most  emi¬ 
nent  botanists  of  the  country.  Professor  Gray  has  kindly  offered  to  work 
up  the  large  and  difficult  family  of  the  Compositce ;  he  has  also  determined 
most  of  the  species  in  the  collection,  and  has  given  every  facility  for  con¬ 
sulting  the  collections  and  library  of  the  “  Gray  Herbarium”  of  Harvard 
University.  Professor  Torrey  will  describe  certain  orders  of  the  Apetalce , 
of  which  he  has  made  a  special  study.  Hr.  Engelmann,  of  St.  Louis,  will 
prepare  the  descriptions  of  the  Cactacece,  and  render  assistance  in  several 
other  orders  to  which  he  has  particularly  devoted  himself.  Professor  Tkur- 
ber,  of  New  York,  will  also  describe  the  grasses;  and  Professor  Eaton,  of 
New  Haven,  the  ferns  and  higher  cryptogamic  plants.  The  carices  collected 
during  the  first  two  years  of  the  Survey  were  examined  and  determined  by 
Hr.  Boott,  of  London,  just  before  his  death.  The  herbarium  of  Hr.  Torrey, 
so  rich  in  Pacific  coast  specimens,  and  those  of  the  Academy  of  Natural 
Sciences  of  Philadelphia  and  of  the  Smithsonian  Institution  have  also  been 
freely  opened  to  Professor  Brewer  for  comparison  and  consultation.  The 
plants  in  the  State  collection  will  all  be  carefully  named,  and  it  is  hoped 
that  the  Legislature  will  make  suitable  provision  for  having  them  placed 


PREFACE. 


XXII 


where  they  will  be  aceesssible  for  comparison  to  all  students  of  this  science 
on  the  Pacific  coast. 

It  is  believed  that  the  botanical  volume  will  be  ready  for  the  press  before 
the  close  of  the  year  1867. 

6.  Zoology. 

The  extensive  acquaintance  of  Dr.  Cooper  with  the  Fauna  of  the  Pacific 
coast,  obtained  previous  to  his  connection  with  the  Geological  Survey,  has 
enabled  him  to  prepare  a  large  amount  of  material  for  the  press,  forming 
the  basis  of  at  least  four  volumes  of  our  Report.  The  illustrations  for  three 
of  these  have  been  in  hand  for  several  months,  and  it  is  hoped  that  they 
will  be  entirely  ready,  so  that  the  volumes  can  go  to  press,  towards  the 
close  of  the  next  year. 

Of  these  volumes,  two  are  devoted  to  the  Mammals  and  Birds,  and  they 
will  be  thoroughly  revised  by  Prof.  Baird,  of  the  Smithsonian  Institution, 
who  will  also  have  charge  of  the  execution  of  the  illustrations.  We  pro¬ 
pose  to  give  a  figure  of  one  of  the  species  in  each  genus;  those  species 
which  have  never  before  been  figured  or  described  will  be  illustrated  by 
large  colored  figures  on  steel  or  stone ;  those  which  are  not  new,  by  wood- 
cuts.  Tie  different  species  of  each  genus  will  be  distinguished  from  each 
other  by  diagrams  of  the  head,  claws,  wings,  and  other  characteristic  parts. 
The  Mammals  will  also  be  fully  illustrated,  the  object  of  this  volume,  as 
well  as  of  all  the  others  of  the  zoological  series,  being  to  furnish  manuals, 
or  text-books,  which  shall  not  only  have  a  permanent  scientific  value,  as 
containing  in  a  condensed  and  systematic  form  all  that  is  known  of  the 
Fauna  of  the  State  of  California  and  its  borders,  but  which  shall  be  prac¬ 
tically  useful  to  those  persons  who  desire  to  ascertain  the  names  and  habits 
of  the  animals  they  may  meet  with  on  the  land  or  in  the  waters  of  the 
Pacific  coast. 

The  description  of  the  fishes  will  form  a  separate  volume,  and  wiU  be  pre¬ 
pared  by  Mr.  Theodore  Gill,  who  will  be  able  to  use,  not  only  the  materials 
and  notes  furnished  by  Dr.  Cooper,  but  also  the  extensive  collections  of  the 
Smithsonian  Institution,  accumulated  during  many  years  of  labor,  by  the 
various  naturalists  who  have  devoted  themselves  on  the  Pacific  coast  to- 
gathering  specimens  in  this  department.  Each  species  will  be  illustrated 
by  a  carefully  drawn  and  engraved  figure,  the  work  being  done  under  Mr. 
Gill’s  immediate  superintendence. 

The  shells  will  also  afford  the  material  for  another  volume,  Dr.  Cooper’s 
collections  of  Mollusca  being  very  extensive,  and  comprising  nearly  two 
hundred  new  species.  As  the  eminent  conchologist,  Mr.  P.  P.  Carpenter, 
has  been  for  a  long  time  specially  devoted  to  the  study  of  the  shells  of  the 
Pacific  coast,  Dr.  Cooper’s  collections  have  been  intrusted  to  him  for  sci¬ 
entific  use,  and  it  is  expected  that  he  will  prepare  one  of  the  volumes  of  our 
zoological  series,  in  which  each  species  will  be  illustrated  by  a  carefully 
drawn  figure. 


XXIV 


PREFACE. 


The  maps  and  sections,  with  perhaps  some  of  the  more  important  illus¬ 
trations  of  the  scenery  of  the  State,  should  be  placed  together  in  one  vol¬ 
ume  or  atlas,  and  will  form  the  proper  conclusion  of  our  series  of  publica¬ 
tions. 

As  thus  planned,  it  will  be  seen  that  we  contemplate  issuing  from  eleven 
to  thirteen  volumes,  as  follows: 


Physical  Geography, . 

General  Geology,  . 

Palaeontology, . 

Economical  Geology,  Mining,  and  Metallurgy, 

*  Botany,  . 

Zoology,  . 

Maps,  Sections,  &c., 


1  * 

2 

2 


1  or  2 
1 

3  or  4 
1 


11  to  13 


The  time  required  to  complete  this  series  will  depend  of  course  on  the 
amount  of  the  appropriations  made  for  the  Survey  by  the  Legislature.  It 
is  hoped  that  the  importance  of  continuing  our  work,  so  as  to  enable  us  to 
finish  up  the  volumes  already  in  progress,  as  given  in  the  above  schedule, 
will  be  appreciated  by  the  people  of  the  State,  and  that  we  shall  have  the 
means  necessary  to  enable  us  to  push  the  work  with  rapidity,  in  which  case 
it  is  believed  that  all  can  be  completed  within  the  next  four  years. 

Some  hesitation  was  felt  in  regard  to  including  the  present  volume  in  the 
permanent  series  of  the  Report,  since  it  is  properly  a  synopsis  of  our  field¬ 
work,  and  a  provisional  report,  rather  than  a  portion  of  a  final  one.  It  was 
finally  concluded  to  allow  it  to  be  considered  as  the  first  volume  of  the  Geo¬ 
logical  series ;  but,  the  number  of  copies  printed  being  small,  it  is  probable 
that  a  revised  and  enlarged  edition  may  be  issued  at  a  future  time,  after  the 
completion  of  the  field-work  of  the  Survey.  The  second  volume  of  the 
General  Geology  will  contain  a  systematic  review  of  the  different  formations 
of  California  and  the  adjacent  States  and  Territories,  together  with  all  the 
generalizations,  and  such  matters  as  cannot  be  properly  prepared  until  we 
have  accumulated  as  large  a  store  of  facts  as  possible.  Had  we  the  mate¬ 
rials  for  such  a  volume  now  in  readiness,  it  could  not  properly  be  issued 
until  our  maps  and  sections  had  been  prepared,  as  these  would  be  almost  in¬ 
dispensable  for  use  in  the  study  of  our  final  geological  results. 

No  provision  has  yet  been  made  by  the  Legislature  for  the  arrangement 
and  exhibition  of  the  collections  made  by  the  Survey,  as  was  contemplated 
in  the  original  Act  of  the  Legislature.  These  collections  are  already  very 
extensive,  embracing  many  thousand  specimens  of  rocks,  fossils,  minerals, 
and  ores,  as  well  as  the  extremely  valuable  suites  in  the  Zoological  and 
Botanical  Departments.  All  these  specimens  are  of  great  importance  as 
illustrating  the  natural  history,  the  geological  structure,  and  the  mineral 
resources  of  the  State.  Such  of  them  as  have  not  been  required  for  use 


X  X  V 


P  R  E  F  A  C  E. 


in  the  preparation  of  our  Report  remain  packed  in  boxes  and  stored  away 
in  the  office  of  the  Survey.  Unfortunately  we  were  obliged,  from  want  of 
room,  to  store  a  portion  of  our  specimens  in  a  so-called  fire-proof  building 
in  San  Francisco,  and  these  have  already  been  burned,  entailing  a  serious 
loss  on  the  Survey  and  the  State.  In  view  of  this  calamity,  it  will  not  be 
necessary  to  enlarge  on  the  necessity  of  providing  a  permanent  and  thor¬ 
oughly  fire-proof  building  for  our  collections,  as  has  already  been  repeat¬ 
edly  urged  by  me  in  my  annual  communications  to  the  Legislature. 

The  only  official  step  thus  far  taken  towards  the  establishment  of  a  State 
Museum  is  the  passage  of  the  following  resolution  by  the  Legislature  of 
1862-3: 


“  Resolved,  By  the  Assembly,  the  Senate  concurring,  That  Professor  J.  I).  Whitney, 
State  Geologist,  John  Swett,  State  Superintendent  of  Public  Instruction,  and  J.  P. 
Houghton,  Surveyor-General,  be  and  they  are  hereby  constituted  a  Board  of  Commis¬ 
sioners,  to  report  to  the  Legislature,  on  or  before  the  second  Monday  of  December,  one 
thousand  eight  hundred  and  sixty-three,  upon  the  feasibility  of  establishing  a  State 
University,  embracing  an  Agricultural  College,  a  ‘School  of  Mines,’  and  a  Museum — 
including  the  Geological  collection  of  this  State  ;  and  that  said  Board  report  such  facts  and 
considerations  as  they  may  deem  important  in  connection  therewith.” 

In  obedience  to  this  requisition  of  the  Legislature,  an  elaborate  Report 
was  submitted  by  the  Board  of  Commissioners,  as  above  constituted,  at  the 
session  of  1863-4,  in  which  Report  the  whole  subject  of  the  organization  of 
a  State  University  was  thoroughly  discussed,  and  the  requirements  of  the 
Constitution,  in  this  respect,  duly  set  forth.  The  establishment  of  a  “  State 
Polytechnic  School,”  having  for  its  object  “  the  professional  training  of 
young  men  in  the  exact  and  natural  sciences  and  their  application  to  arts, 
manufactures,  mining,  and  agriculture,”  was  strongly  recommended  to  the 
Legislature.  It  was  also  proposed  that  the  entire  collections  of  the  Geo¬ 
logical  Survey  should  be  placed  in  a  suitable  fire-proof  building,  in  which 
should  be  ample  accommodation  for  displaying  and  storing  them,  as  well  as 
room  for  a  library,  a  laboratory,  and  an  office  for  the  Survey,  together  with 
lecture-rooms  and  other  conveniences  necessary  for  a  Scientific  School,  for 
which  purpose  the  building  was  to  be  used  after  the  completion  of  the  Sur¬ 
vey.  This  would  have  been  the  first  step  towards  the  establishment  of  a 
State  University,  provided  for  long  since  by  the  Constitution,  and  for  which 
the  funds  have  been  furnished  by  the  United  States.  The  interest  on  the 
money  given  by  Congress  for  the  establishment  of  a  University  has  thus  far 
been  applied  to  another  object;  but  it  is  evident  that  the  people,  through 
the  Legislature,  are  bound  in  honor  to  see  that  the  trust  accepted  by  the 
State,  and  incorporated  in  their  own  Constitution,  should  be  sacredly  com¬ 
plied  with. 

For  the  details  of  the  organization  of  the  Polytechnic  School  proposed  by 
the  Commissioners,  reference- may  be  made  to  their  Report,  contained  in  the 
Public  Documents  of  the  State  for  the  year  1864. 


GEOL.  VOL.  I.  —  D 


XXVI 


PREFACE. 

To  those  gentlemen  in  California,  as  well  as  in  the  Eastern  States,  who 
have  aided  me,  in  various  ways,  in  the  prosecution  of  the  arduous  undertak¬ 
ing  in  which  I  have  been  engaged  for  the  last  five  years,  my  warmest  thanks 
are  due ;  but  especially  to  my  assistants,  who  have  all  labored  zealously  for 
the  interests  of  the  State  and  the  Survey,  regardless  of  hardships  or  dangers. 

In  closing  this  preface,  I  will  simply  add  an  extract  from  my  address 
before  the  Legislature,  in  1862,  in  which  the  reasons  why  the  Geological 
Survey  of  California  should  be  continued  on  the  broad  basis  of  the  original 
Act  under  which  it  was  organized,  are  succinctly  set  forth. 

“  I  submit,  therefore,  that  California  needs  a  Geological  Survey,  for  the 
following  good  and  sufficient  reasons: 

u  First.  To  furnish  a  basis  for  detailed  explorations  for  farther  deposits  of 
metallic  and  mineral  treasures,  by  limiting  the  field  of  research  for  the 
numerous  prospectors  always  engaged  in  the  search  for  useful  ores;  so  that 
every  man  will  be  working  where  his  labor  will  tell,  and  not  throwing  it 
away  on  undertakings  which  a  comprehensive  view  of  the  mode  of  occur¬ 
rence  and  geological  position  of  our  economically  valuable  materials  will 
show  to  be  a  mere  waste  of  money,  time,  and  energy. 

“  Second.  To  insure  permanent  working  and  economical  development  of 
what  is  discovered,  by  giving  every  one  the  means  of  knowing  beforehand 
how  his  discoveries  may  be  turned  to  the  best  account,  how  much  it  will 
cost  to  open  his  mine,  how  much  to  reduce  his  ores,  what  form  to  give  his 
products,  and  where  and  in  what  quantity  they  can  be  disposed  of.  On 
subjects  of  this  kind,  we  are  constantly  applied  to  for  information,  and  are 
always  ready  to  advise  to  the  best  of  our  ability.  And,  if  not  now,  we 
shall,  as  we  become  more  fully  acquainted  with  all  the  necessary  conditions, 
be  able  to  render  essential  service  in  this  line,  as  our  statements  will  be 
recognized  as  being  based  on  extensive  researches,  and  entirely  disinterested; 
and  in  our  final  report  we  shall  throw  all  possible  light  on  these  subjects,  so 
that  it  will  not  be  our  fault  if  the  man  about  to  embark  in  any  enterprise 
connected  with  ores  or  mineral  substances  will  not  find  in  our  work  some¬ 
thing  which  will  materially  aid  him  in  his  undertaking,  or  at  least  prevent 
a  foolish  waste  of  money  on  the  impracticable. 

“  Third.  We  need  a  Geological  Survey  in  order  that  the  resources  of  the 
State  may  be  made  known  to  the  world,  under  official  guaranty  of  correct¬ 
ness,  and  in  detail,  so  that  not  only  our  own  capitalists,  but  those  of  other 
countries,  may  have  opened  to  them  a  field  for  investment,  in  regard  to 
which  they  will  be  possessed  of  such  definite  information  that  they  may  feel 
that  they  are  not  entering  on  a  blind  speculation  when  putting  their  money 
into  a  mine. 

“  Fourth.  We  need  such  a  Survey  as  was  contemplated  by  the  Act  under 
which  we  commenced  our  work,  in  order  that  the  educational  interests  of 
the  State  maybe  advanced — our  schools,  colleges,  and  University  furnished 
with  a  scientific  basis  for  instruction  in  the  different  branches  of  Geology 
and  Natural  History,  and  with  text-books  in  which  the  necessary  informa- 


P  R  E  F  A  C  E.  XXV11 

tion  m a}r  be  found  as  to  the  forms  of  animal  and  vegetable  life  occurring 
on  the  Pacific  coast. 

“  Fifth.  We  need  a  Geological  Survey  in  order  to  show  to  the  world  that 
the  State  is  willing;  to  contribute  something  towards  the  advancement  of 
science,  and  that  we  may  not  be  subjected  to  the  mortification  of  having 
the  rich  harvest  of  facts  which  California  spreads  out  before  us,  left  unga¬ 
thered,  or  only  partially  reaped,  for  the  benefit,  and  by  the  efforts  of  other 
States  and  countries.” 

J.  D.  Whitney. 

November  1st,  1865. 


r  i  9 


* 


PART  I. 


GEOLOGY  OF  THE  COAST  RANGES. 


CHAPTER  L 

INTRODUCTORY. 

The  term  “  Coast  Ranges”  is  one  which  will  be  frequently  employed 
in  this  Report,  as  it  is  one  in  common  use  in  California.  It  is  the  de¬ 
signation  of  a  great  group  of  mountain  ranges,  naturally,  and  almost 
necessarily,  applied  to  distinguish  them  from  the  ranges  of  the  Sierra 
Nevada,  and  for  this  purpose  familiar  to  all  residents  on  the  Pacific 
coast.  When,  however,  we  seek  to  define  the  term  Coast  Range  with 
the  precision  desirable  in  a  scientific  work,  we  soon  discover  that  an 
exact  definition  of  it  is  a  difficult  matter,  and  that  a  discussion  of  its 
meaning  will  soon  lead  us  into  regions  where  a  knowledge  of  both  the 
geography  and  geology  of  the  State  will  be  necessary  for  understand¬ 
ing  all  the  elements  which  are  involved  in  what  is  apparently  so  simple 
a  question.  The  first  part  of  this  Report  will  be  occupied  with  the 
geology  of  th*e  Coast  Ranges,  the  second  with  that  of  the  Sierra  Ne¬ 
vada,  and  it  will  not  be  until  we  have  passed  over  this  ground,  that  we 
can  enter  understandingly  upon  a  discussion  of  the  question,  how  and 
why  shall  the  line  he  drawn  separating  the  two  systems  of  mountain 
ranges  from  each  other.  In  the  meantime,  however,  some  general 
considerations  on  the  topography  of  the  Coast  Ranges  will  be  conve¬ 
nient  as  an  introduction  to  what  is  to  follow  in  regard  to  its  geology, 
reserving  the  consideration  of  the  more  difficult  theoretical  portion  of 
the  subject  for  a  future  chapter. 

GEOL.  VOL.  I. — 1 


2 


GEOLOGY  OF  THE  COAST  RANGES. 


Between  the  parallels  of  35°  and  40°  there  is  no  difficulty  in  sepa¬ 
rating  the  Coast  Ranges  from  the  Sierra  Nevada.  The  traveller,  pass¬ 
ing  up  the  valleys  of  the  Sacramento  or  the  San  Joaquin,  observes  at 
a  distance  of  twenty  or  thirty  miles,  on  either  hand,  a  continuous  wall 
of  mountains,  which  may  appear  in  the  dim  distance  to  the  inexperi¬ 
enced  eye  as  a  simple  and  narrow  range,  hut  both  of  which  in  reality 
are  broad  belts  of  elevated  ranges,  the  one  averaging  forty,  the  other 
seventy  miles  in  width,  of  which  the  detailed  structure  is  exceedingly 
complicated,  and  whose  grand  dimensions  can  only  be  appreciated  by 
those  who  have  penetrated  to  their  deepest  recesses.  Suffice  it  to  say, 
for  the  present,  that  in  the  Sierra  Nevada  on  the  one  hand,  and  the 
Coast  Ranges  on  the  other,  we  have  two  groups  of  mountain  chains, 
which  for  length  and  average  elevation  are  but  little,  if  at  all,  inferior 
to  the  Alps  and  the  Appalachians,  those  grand  features  of  the  earth’s 
surface  which  have  for  so  many  years  occupied  the  attention  of  a  host 
of  scientific  observers,  and  lovers  of  natural  scenery.  Of  the  eastern 
series  of  ranges,  the  most  distant  and  loftiest  elevations  are  never 
entirely  bare  of  snow,  and  for  a  large  portion  of  the  year  are  exten¬ 
sively  covered  with  it ;  while  the  western  ones,  in  the  central  portion 
of  the  State  at  least,  are  only  occasionally  and  rarely  whitened  on  their 
highest  summits,  and  for  a  brief  period  of  the  winter.  Hence  the 
eastern  heights  were  long  since  known  to  the  Spaniards  as  the  “  Sierra 
Nevada,”  or  Snowy  Range;  sierra  being  almost  the  exact  equivalent 
of  our  word  range  or  mountain-chain.  The  group  of  mountains  on 
the  western  side,  and  nearer  the  ocean,  naturally  received  the  designa¬ 
tion  of  “  Coast  Ranges,”  although  this  appears  to  be  a  term  of  natural 
Anglo-American  growth,  and  not  a  translation  from  the  Spanish,  those 
using  this  language  having,  so  far  as  noticed,  no  word  in  general  use 
equivalent  to  “  Coast  Range,”  but  calling  the  different  groups  of  moun¬ 
tains,  or  minor  chains  separated  by  narrow  valleys,  after  the  names  of 
various  saints ;  indeed,  nearly  exhausting  the  calendar.  In  many  cases 
these  names  are  uncertain,  and  frequently  the  same  range  is  known  to 
residents  along  different  portions  of  it  by  different  names,  which  are 
generally  the  same  as  those  given  to  the  dominating  peak  in  the 
immediate  vicinity.  Thus  the  Monte  Diablo  Range  is  so  called  from 
the  conspicuous  point  of  that  name,  which,  although  not  as  high  as 


INTRODUCTORY. 


3 


other  summits  of  the  same  range,  from  its  peculiar  isolated  position 
is  a  sort  of  natural  landmark  over  a  large  part  of  Central  California. 

Between  the  35th  and  40th  parallels,  as  before  remarked,  there  is  no 
difficulty  in  distinguishing  the  Coast  Ranges  from  the  Sierra,  as  the 
broad  valleys  of  the  Sacramento  and  the  San  Joaquin  form  a  complete 
separation  of  the  two  systems  of  mountain-chains;  but  if  we  go  north 
or  south  of  these  limits,  the  condition  of  things  changes  greatly,  as  will 
be  evident  to  any  one  inspecting  a  map  of  the  State.  In  the  neighbor¬ 
hood  of  the  Tejon  Pass,- which  is  in  about  35°  of  latitude,  the  ridges  of 
the  Sierra  and  the  Coast  Ranges  become  continuous,  and  it  is  only  on 
geological  considerations  that  the  line  of  division  between  the  two 
systems  can  be  drawn,  the  topography  alone  giving  no  clue  as  to  where 
the  one  ceases  and  the  other  begins.  Thus  the  question  has  been  re¬ 
peatedly  asked  during  the  continuance  of  the  survey : — What  is  the 
proper  name  to  apply  to  the  ranges  south  of  Fort  Tejon?  Do  they 
belong  to  the  Sierra,  or  to  the  Coast  Mountains  ?  The  same  is  the  case 
with  regard  to  the  mountains  north  of  the  head  of  the  Sacramento 
Valley.  Above  Shasta  City  (latitude  40°  35')  the  ranges  close  in  on 
all  sides,  and  to  the  traveller  threading  the  innumerable  canons  there 
seems  to  be  no  clue  to  the  labyrinth  of  chains  and  no  possibility  of 
preserving  the  distinction  between  Coast  Range  and  Sierra.  Farther 
on  in  this  Report  this  question  will  be  discussed,  in  the  light  of  the 
geological  information  which  has  been  previously  laid  before  the 
reader ;  at  present  such  general  topographical  considerations  need  only 
be  presented  as  shall  render  the  systematic  division  of  this  volume 
intelligible.  For  a  complete  review  of  the  physical  features  of  the 
State,  a  future  volume  of  this  Report,  exclusively  devoted  to  physical 
geography,  must  be  awaited. 

In  order  to  bring  vividly  before  the  mind  the  grand  simplicity  of 
the  topographical  features  of  California,  we  may  draw  on  the  map  of 
the  State  five  equidistant,  parallel  lines,  having  a  direction  of  N.  31° 
W.,  and  55  miles  apart.  Let  the  middle  one  of  these  be  drawn  at  the 
western  base  of  the  Sierra  Nevada,  touching  the  edge  of  the  foot-hills, 
as  it  will  be  found  to  do  with  the  given  direction,  from  Visalia  to  Red 
Bluff,  the  first  parallel  line  east  of  this,  drawn  at  55  miles  distance, 
will  pass  through  or  very  near  the  highest  points  of  the  Sierra,  begin- 


4 


GEOLOGY  OF  THE  COAST  RANGES. 


ning  with  Mount  Shasta,  on  the  north,  and  touching  in  succession 
towards  the  south,  tirst  Lassen’s  Butte,  then  Spanish  Peak,  Pilot  Peak, 
the  Downieville  Buttes,  Pyramid  Peak,  Castle  Peak,  Mount  Dana,  and 
beyond  this,  keeping  close  along  the  main  crest  of  the  Sierra,  across 
the  culminating  points  of  the  chain  which  lie  to  the  south  of  Mount 
Dana,  of  which  the  position  has  only  recently  been  determined,  and 
which  have  not  yet  been  laid  down  on  any  published  map.  Indeed  there 
is  no  map  of  the  Sierra,  as  yet,  on  which  the  main  ridge  is  accurately 
given,  and  the  determination  of  the  more  or  less  precise  accordance  of 
the  line  indicated  above  with  all  the  dominating  peaks  must  await  the 
completion  and  publication  of  our  topographical  work.  It  is  sufficient, 
for  the  present,  to  say  that  the  line  drawn  through  the  culminating 
peaks  of  the  Sierra,  for  a  distance  of  almost  500  miles,  is  very  nearly 
a  straight  one,  and  that  its  direction  is  1ST.  31°  W.,  and  that  we  may 
call  this  the  main  axial  line  of  California,  while  it  will  be  interesting  to 
notice  to  how  considerable  an  extent  the  great  topographical  features 
of  the  State  will  be  found  to  be  subordinate  to  it. 

The  next  parallel  line  east  of  this,  still  at  the  same  distance  of  55 
miles,  crosses  a  series  of  depressions,  mostly  occupied  by  lakes,  which 
we  may  consider  as  representing  the  eastern  base  of  the  Sierra.  These 
lakes  are  the  Klamath,  Wright,  Pyramid,  Walker,  Death  Valley,  and 
Soda  Lake,  the  sink  of  the  Mohave.  At  its  southern  extremity,  it 
marks  the  confluence  of  the  Colorado  and  Gila  Rivers. 

The  first  line  to  the  west  of  the  central  one,  or  that  drawn  at  the  west¬ 
ern  base  of  the  Sierra,  will  be  found  to  follow  very  closely  the  eastern 
edge  of  the  Coast  Ranges,  from  the  neighborhood  of  Kern  Lake  to  that 
of  Clear  Lake,  a  distance  of  over  300  miles.  The  second  line  west  of 
the  central  one,  and  the  last  of  the  series  of  parallel,  equidistant  ones, 
represents,  as  nearly  as  possible,  the  coast  line  of  the  Pacific;  or,  in 
other  words,  the  western  base  of  the  Coast  Ranges.  By  this  curious 
arrangement,  which  must  be  due  to  the  working  of  great  cosmical 
forces,  and  which  is  evidently  not  the  result  of  chance,  we  have  the 
State,  at  least  that  portion  of  it  between  Fort  Tejon  and  Red  Bluff, 
divided  into  four  belts  of  nearly  equal  width  (a  portion  of  the  most 
easterly  one,  however,  falling  within  the  limits  of  the  State  of  Nevada), 
which  are  designated  as  follows,  naming  them  in  order  from  east  to 


INTRODUCTORY. 


west:  the  Eastern  Slope,  the  Sierra,  the  Great  California  Valley,  and 
the  Coast  Ranges. 

This  arrangement  of  the  physical  features  of  the  State  holds  good 
for  a  length  of  400  miles,  in  the  direction  of  the  main  axial  line,  and 
this  division  of  California  is  the  largest  and  by  far  the  most  important, 
comprising  almost  the  whole  of  the  agricultural  and  the  greater  part  of 
the  mining  districts,  and  may  be  designated  as  Central  California;  that 
portion  to  the  south  of  a  line  drawn  at  right  angles  to  the  main  axial 
line,  or  N.  59°  E. — S.  59°  W.,  through  Fort  T£jon,  may  he  called  the 
Southern  Division ;  that  north  of  a  parallel  line  passing  through  Fort 
Reading,  may  be  also  designated  as  the  Northern  Division  of  the  State. 
This  perhaps  is  the  most  simple  and  convenient  division  into  a  small 
number  of  parts  which  can  be  made,  and  it  approximates  pretty 
closely  to  the  general  and  natural  recognition,  among  the  people,  of  a 
Northern,  Central,  and  Southern  California.  So  peculiar,  however, 
is  the  detailed  structure  of  the  State,  that  it  is  difficult  to  find  any 
thoroughly  satisfactory  arrangement  of  its  parts ;  and  in  view  of  our 
as  yet  imperfect  knowledge  of  all  the  conditions  influencing  the  deci¬ 
sion  of  this  question,  the  matter  will  be  left  in  abeyance  until  the  pub¬ 
lication  of  a  final  volume  on  geology  or  physical  geography.  In  the 
meantime  a  more  or  less  artificial  system  will  be  followed,  based  how¬ 
ever  on  the  well-marked  division  of  the  mountain  chains  into  Sierra 
and  Coast  Range  systems. 

As  the  Coast  Ranges  in  the  vicinity  of  the  Bay  of  San  Francisco 
have  been  more  carefully  studied  by  the  Survey  than  any  other  portion 
of  the  State,  and  especially  more  so  than  the  continuations  of  the  same 
ranges  north  and  south,  it  will  be  proper  to  take  up  the  description  of 
this  region  first,  since  its  geological  structure  can  be  made  out  in  a 
more  detailed  manner  than  that  of  other  districts,  where  of  necessity 
less  labor  has  been  expended. 

Two  difficulties  beset  us  constantly  in  the  study  of  the  Coast  Ranges  : 
one  is,  the  similarity  in  lithological  character  of  rocks  of  different  geo¬ 
logical  ages ;  the  other,  the  comparative  paucity  of  fossils  by  which  the 
different  sets  of  strata  might  be  identified  and  traced  over  the  wide 
extent  of  territory  they  occupy,  where  lithological  characters  were 
insufficient  for  this  purpose.  It  may  also  be  noticed  that  the  preva- 


G 


GEOLOGY  OF  THE  COAST  RANGES. 


lence  of  metamorphic  or  chemical  changes  in  the  rocks  has  often 
obliterated  all  the  evidences  of  stratification,  while  the  thorough  me¬ 
chanical  crushing  which  the  beds  have  undergone,  over  many  exten¬ 
sive  districts,  has  often  rendered  the  deciphering  of  their  stratigraphical 
position  a  task  of  extreme  difficulty.  In  consequence  of  these  condi¬ 
tions,  while  our  general  conclusions  may  fairly  he  accepted  as  making 
a  reasonable  approach  to  correctness  and  as  furnishing  a  sound  basis 
for  future  explorations,  we  cannot  avoid  great  deficiencies  in  the  details, 
which  only  the  patient  labor  of  many  years,  on  the  part  of  future 
students  in  this  region,  will  be  able  to  supply. 

As  the  geographical  basis  on  which  this  portion  of  our  work  is 
founded,  and  as  the  necessary  guide  in  its  perusal,  we  refer  to  the 
topographical  and  geological  “  Map  of  the  Region  adjacent  to  the  Bay 
of  San  Francisco,”  drawn  by  Mr.  Hoffmann,  and  compiled  from  all 
the  sources  within  our  reach,  the  topography  being  almost  exclusively 
original,  and  the  result  of  his  own  labors.*  This  map  embraces  the 
region  from  near  Santa  Cruz  north  to  Sonoma,  Hapa,  and  Petaluma, 
and  it  extends  east  and  west  from  Punta  de  los  Reyes  to  Corral  Hollow. 
The  area  of  land  which  it  covers  is  about  4248  square  miles,  which  is 
just  twice  that  of  the  State  of  Delaware,  and  only  lacks  two  hundred 
square  miles  of  equalling  that  of  Connecticut.  As  near  as  can  be 
ascertained,  from  an  examination  of  the  results  of  the  census  of  1860, 
it  contains  one-third  of  the  population  of  the  State,  and  has  about 
thirty  inhabitants  to  the  square  mile,  the  average  density  of  the  popu¬ 
lation  of  California  being  but  little  over  two  to  the  square  mile. 

The  region  adjacent  to  the  Bay  of  San  Francisco  may,  without  hesi¬ 
tation,  be  called  the  garden  of  California;  it  includes  her  most  fertile 
valleys  and  her  richest  and  best  watered  farming  lands.  Its  climate, 
tempered  by  the  proximity  of  the  Golden  Gate,  through  which  enter 


*  This  map  will  be  issued  by  itself  as  soon  as  the  engraving,  which  is  necessarily  the 
work  of  much  time,  has  been  completed.  It  will  also  form  one  of  the  series  of  maps 
embraced  in  a  volume  of  the  series  of  the  publications  of  the  Geological  Survey,  which 
volume  will  be  especially  devoted  to  maps,  sections,  and  other  illustrations  which  cannot 
well  be  bound  up  with  the  text.  The  various  maps  issued  by  the  Survey  will  be  furnished 
either  plain,  or  with  the  geology  colored  upon  them,  as  may  "he  desired,  so  that  they  may 
be  used  either  as  geographical  or  geological  guides  in  the  regions  which  they  embrace. 


INTRODUCTORY. 


7 


the  moist  and  cooling  ocean  breezes,  is  as  near  perfection  as  can  be 
desired.  That  portion  represented  on  our  map  contains  less  than  one- 
fortieth  of  the  area  of  the  State,  but  has  one-third  of  its  population ; 
and,  so  rapid  is  the  growth  of  San  Francisco,  that  it  will  soon  comprise 
one-half,  and  probably  in  time  a  considerably  larger  proportion.  Hence 
the  propriety  of  preparing  a  map  of  this  region  on  a  scale  greater  than 
that  which  we  shall  be  able  to  use  for  other  portions  of  the  State ;  and 
hence,  also,  the  convenience  and  possibility  of  working  up  its  geology 
more  in  detail  than  that  of  other  districts,  of  which  our  maps  are  much 
less  complete,  for  without  accurate  maps  accurate  geology  is  simply 
impossible. 

On  examining  the  map,  it  will  be  seen  at  once  how  large  a  portion 
of  the  region  in  question  is  of  a  mountainous  character.  With  the 
exception  of  the  Bays  of  San  Francisco,  San  Pablo,  and  Suisun,  and 
the  valleys  adjacent,  which  are  in  reality  all  parts  of  one  connected 
whole,  only  not  entirely  covered  by  water,  there  are  no  extensive  plains. 
The  most  superficial  glance  at  the  map  will  also  reveal  the  fact,  that 
the  ranges  of  mountains  have  a  predominant  trend  in  one  direction, 
namely,  about  northwest  and  southeast,  and  that  the  main  features  of 
the  surface,  such  as  the  position  of  the  hills,  valleys,  plains,  and  water¬ 
courses,  are  closely  dependent  on  the  fact  of  the  folding  of  the  surface 
having  taken  place  in  this  direction.  The  topographical  elements  are 
in  the  line  of  northwest  and  southeast,  or  nearly  at  right  angles  to  it. 
This,  indeed,  is  mainly  true  throughout  the  Coast  Ranges. 

There  are  many  general  considerations  with  regard  to  the’ Coast 
Ranges  which  cannot  well  be  entered  upon  until  after  their  geological 
structure  has  been  explained,  and  these  will,  consequently,  be  deferred 
to  a  later  portion  of  this  volume,  and  we  may  now  commence  with  the 
Monte  Diablo  Range. 


8 


GEOLOGY  OF  THE  COAST  RANGES. 


CHAPTER  II. 

THE  MONTE  DIABLO  RANGE. 

Section  I. — Introductory. 

The  group  of  mountain  chains  to  which  the  name  “  Monte  Diablo 
Range”  is  applied,  extends  from  the  Straits  of  Carquines  and  San 
Pablo  Bay  in  a  southeastern  direction  to  about  latitude  36°  30'.  It  is 
limited  on  the  east  by  the  plain  of  the  San  Joaquin,  and  on  the  west  it 
has  the  Bay  of  San  Francisco  and  the  Valley  of  Santa  Clara  to  isolate 
it  from  the  other  division  of  the  Coast  Ranges.  In  its  northern  exten¬ 
sion,  the  Monte  Diablo  Range  is  easily  defined ;  hut  to  the  south  it 
widens  and  inosculates  with  other  ranges,  or  spurs,  falling  into  it  from 
the  northwest,  until  finally  uniting  with  the  extreme  western  members 
of  the  great  group  of  the  Coast  Ranges  it  forms  the  broad  region  of 
high  rolling  hills,  intersected  by  a  labyrinth  of  narrow  valleys,  which 
lies  between  the  parallels  of  35°  and  35°  30',  and  where  distinctness  of 
nomenclature  for  the  different  groups  of  elevations  is  almost  entirely 
lost.  For  convenience,  and  as  representing  as  nearly  as  possible  a 
natural  division  of  the  Coast  Ranges,  the  Monte  Diablo  Range  may  he 
considered  as  terminating  to  the  south  in  the  low  ridges  running  out 
into  the  San  Joaquin  plain  at  the  head  of  Las  Gatas  Creek,  in  latitude 
36°  20'.  As  thus  defined,  the  range  is  about  one  hundred  and  fifty 
miles  long  and  from  twenty  to  thirty  broad.  For  fifty  miles  on  its 
southwestern  edge  it  is  with  difficulty  separated  from  the  Gavilan 
Range,  the  two  having  only  the  narrow  valley  of  the  San  Benito  be¬ 
tween  them  for  nearly  that  distance,  and  finally  uniting  in  the  most 
unbroken  connection  with  each  other. 

The  Monte  Diablo  Range  is  made  up  of  a  complicated  series  of 
ridges,  mountains,  and  valleys,  when  examined  in  detail,  and  part  of 
it  is  exceedingly  rough  and  very  little  traversed  by  any  class  of  men, 
not  even  by  hunters  or  explorers.  How  little  was  really  known  of 
the  geography  of  the  chain  may  be  inferred  from  the  fact  that  there 
existed  in  it  peaks  higher  than  Monte  Diablo  and  in  sight  from  the 


THE  MONTE  DIABLO  RANGE. 


9 


elevated  portion  of  the  city  of  San  Francisco  :  this  fact  was  made  known 
hy  the  explorations  of  the  survey. 

That  portion  of  the  Monte  Diablo  Range  which  lies  north  of  Alameda 
Canon  and  west  of  the  Valley  of  San  Ramon,  is  usually  called  in  San 
Francisco  the  Contra  Costa  Range,  or  the  Contra  Costa  Hills,  these 
being  the  elevations  which  rise  behind  the  Bay  of  San  Francisco,  and 
which  are  so  conspicuously  in  view  from  the  city  itself.  The  mass  of 
the  range  north  of  Livermore’s  Pass,  and  east  of  the  San  Ramon  Val¬ 
ley,  is  that  particular  portion  of  the  range  to  which  the  name  of  Monte 
Diablo,  that  of  its  culminating  point,  is  most  usually  applied.  To  that 
extensive  and  rugged  mountain  district,  which  lies  south  of  the  Contra 
Costa  Hills  and  the  Corral  Hollow  Pass,  it  will  be  convenient  to  give 
names  corresponding  to  the  various  subdivisions  into  which  it  may 
most  naturally  be  broken.  To  the  region  between  Corral  Hollow  Pass 
and  Pacheco’s  Pass  the  name  of  the  Mount  Hamilton  Division  may  be 
given,  from  that  of  its  culminating  point.  That  portion  which  lies 
between  Pacheco’s  and  the  Panoclie  Passes  may  be  designated  as  the 
Panoche  Division ;  of  this,  Pacheco’s  and  the  Santa  Anna  Peaks  are 
the  most  conspicuous  points.  The  next  more  southerly  division  of  the 
main  range,  or  that  between  the  Panoche  and  Estrella  Passes,  may  be 
called  the  San  Carlos  Division,  from  its  dominating  peak,  which  is  also 
the  highest  point  of  the  whole  Monte  Diablo  Range.  Finally,  the 
most  southerly  division  lies  between  the  Estrella  and  Roble  Passes, 
and  to  this  the  name  of  Estrella  may  be  given,  from  the  pass  and  river 
of  that  name. 

In  traversing  the  plain  of  the  San  Joaquin,  issuing  from  Pacheco’s 
Pass,  or,  better  still,  from  Livermore’s  Pass,  and  taking  the  road  to 
Visalia,  the  various  masses  of  the  Monte  Diablo  Range  are  well  seen 
and  may  be  studied  and  compared  in  their  general  outline  and  magni¬ 
tude.  The  Livermore  Pass  is  much  lower  than  either  of  the  others, 
there  being  no  such  break  through  the  chain  anywhere  to  the  south. 
The  high  mass  of  Mount  Hamilton  is  conspicuous,  and  it  is  evident 
that  the  ridges  in  that  part  of  the  chain  run  out  into  and  sink  beneath 
the  plain.  Pacheco’s  Peak  and  the  other  high  points  in  its  vicinity  are 
conspicuous,  but  less  so  than  from  the  western  side  of  the  chain.  Low 
sandstone  hills  stretch  along  in  front  of  them  and  south  to  beyond 

GEOL.  VOL.  I. — 2 


10 


GEOLOGY  OF  THE  COAST  RANGES. 


San  Carlos  Peak,  looking;  like  a  wide  and  elevated  terrace  in  the  dis- 
tance,  much  eroded  into  canons,  and  very  dry  and  bare,  except  in  the 
early  spring  after  a  winter  of  abundant  rain.  The  mass  of  San  Carlos 
seems  the  highest  and  grandest  of  the  whole  chain,  the  most  elevated 
point  being  a  few  miles  south  of  the  mine  of  that  name,  near  New 
Idria ;  this  high  mass,  however,  extends  south  fifteen  or  twenty  miles, 
the  southern  portion  having  a  very  rough  outline,  crowned  with  a  battle¬ 
ment  of  rock,  which  is  conspicuous  from  a  long  distance.  South  of  this 
is  the  depression,  through  which  is  the  Estrella  Pass,  the  trail  ascending 
Chelone  Creek,  from  the  Estrella  Ranch,  and  crossing  over  the  Arroyo 
las  Gatas;  this  depression,  however,  is  not  a  low  one.  South  of  this  is 
another  mass  of  mountains  of  considerably  less  elevation  than  the  San 
Carlos,  and  the  chain  sinks  very  low  again  as  we  approach  Paso  Roble. 

The  following  table  shows  at  a  glance  the  principal  facts  known  with 
regard  to  names  and  elevations  of  the  various  subdivisions  of  the  Monte 
Diablo  Range,  the  highest  peaks  and  the  passes  : 


Subdivision. 

Monte  Diablo. 
Mount  Hamilton. 
Panoche. 

San  Carlos. 
Estrella. 


Name  and  elevation  of 
dominating  peak. 

Monte  Diablo,  3856. 
Mount  Hamilton,  4440. 
Mariposa  Peak,  3700. 
San  Carlos,  4977. 

? 


Name  and  height  of  pass, 
separating  it  from  next 
more  southern  division. 

Livermore  Pass,  686. 
Pacheco’s  Pass,  1470. 
Panoche  Pass,  2500. 
Estrella,  ? 

Paso  Roble,  ? 


The  Estrella  and  Roble  Passes  have  never  been  instrumentally  ex¬ 
plored. 

In  describing  each  of  these  divisions  it  will  be  convenient  to  begin 
with  the  Monte  Diablo  group,  and  to  proceed  southward.  The  explo¬ 
rations  on  which  our  information  is  based  and  the  lines  of  section 
examined  in  working  out  the  geology  of  the  Monte  Diablo  Range 
were  as  follows : 

In  1861,  the  chain  was  passed  through  in  a  southeast  direction  from 
San  Juan  to  the  New  Idria  mines,  the  road  traversing  the  range  diago¬ 
nally  for  a  distance  of  fifty  or  sixty  miles.  The  most  southerly  point 
visited  was  San  Carlos  Peak,  which  is  about  one  hundred  and  forty- 
five  miles  from  the  northwest  extremity  of  the  chain.  Another  excur¬ 
sion  was  made  to  Pacheco’s  Pass  and  its  vicinity,  and  thence  the  party 


CONTRA  COSTA  HILLS. 


11 


travelled  along  the  east  side  of  the  San  Jose  Valley  and  the  Bay  of 
San  Francisco  for  a  distance  of  seventy  miles,  making  frequent  offsets 
into  the  chain  to  the  east.  Thence  a  line  of  section  from  Oakland  to 
Monte  Diablo  itself  was  examined  and  the  vicinity  of  the  mountain  as 
far  south  as  Corral  Hollow,  as  well  as  the  region  adjacent  to  Calaveras, 
Livermore’s,  and  San  Ramon  Valleys.  In  1862  the  vicinity  of  Monte 
Diablo  was  again  visited  and  explored  more  in  detail  than  the  year 
before,  so  much  so  as  to  admit  of  an  accurate  topographical  map  being 
constructed.  This  work  was  participated  in  by  all  the  corps,  and  after¬ 
wards  the  east  side  of  the  Monte  Diablo  and  Mount  Hamilton  groups 
were  explored  with  some  care  by  Messrs.  Brewer  and  Gabb,  and  the 
principal  points  in  the  topography  of  that  before  utterly  unknown 
region  determined,  by  Mr.  Hoffmann.  This  party  returned  north 
through  Pacheco’s  Pass,  on  their  way  re-examining  some  of  the  points 
left  unvisited  on  the  previous  journey  up  the  valley.  Many  short  ex¬ 
cursions  were  made  at  various  times  into  the  vicinity  of  Monte  Diablo 
and  the  Contra  Costa  Hills  by  all  the  members  of  the  corps. 


Section  II. — Contra  Costa  Hills. 


The  subordinate  group  of  elevations  lying  west  of  Martinez  and  the 
San  Ramon  and  Livermore  Valleys,  is  known  as  the  Contra  Costa 
Hills ;  they  extend  through  the  county  of  that  name  into  Alameda  and 
Santa  Clara  Counties,  and  finally  become  merged  in  the  Mount  Hamil¬ 
ton  Division  of  the  Monte  Diablo  Range.  These  hills  are  separated 


from  the  principal  mountain  mass  of  Monte  Diablo  by  a  system  of  val¬ 
leys  extending  for  about  forty-five  miles,  and  preserve  a  somewhat 
distinctive  character  for  some  fifteen  miles  farther,  losing  their  identity 
entirely  about  the  head  of  Calaveras  Valley.  They  are  made  up  of 
Tertiary  and  Cretaceous  strata,  usually  but  little  metamorphosed, 
although  a  belt  extending  along  their  western  side  is  considerably 
altered  from  its  original  character. 

Beginning  at  the  northwest  extremity  of  the  group,  at  Martinez,  we 
have  in  the  immediate  vicinity  of  that  place  Cretaceous  strata,  well 
exposed  in  the  bluffs  along  the  Straits  of  Carquines.  Here  the  rocks 
observed  are  sandstones,  shales,  and  argillaceous  limestones,  the  latter 


12 


GEOLOGY  OF  THE  COAST  RANGES. 


forming  bands  and  lenticular  masses  in  the  shales,  generally  hut  a  few 
inches  thick,  although  sometimes  as  much  as  three  feet.  Their  strike 
is  usually  about  H.  42°  W.,  varying,  however,  from  IN’.  39°  W.  to  H. 
44°  W.,  and  they  dip  southwest  at  an  angle  of  from  35°  to  60°. 

The  rocks  near  Martinez  have  furnished  a  large  number  of  species 
of  Cretaceous  fossils,  having  been  most  diligently  examined  by  Mr.  E. 
Mathewson.  Over  a  hundred  forms,  mostly  new,  have  been  obtained 
here  by  this  gentleman  and  the  members  of  the  survey,  for  a  list  of 
which  see  the  table  of  localities  of  Cretaceous  fossils  in  the  volume 
devoted  to  the  Palaeontology  of  these  rocks.  Both  divisions  of  the 
Cretaceous  are  represented  here. 

In  passing  along  the  shore  of  the  Straits  of  Carquines,  west  of  Mar¬ 
tinez,  the  Cretaceous  strata  occur  for  about  seven  miles,  and  are  made 
up  of  shales  and  sandstones,  the  former  containing  frequent  thin  layers 
of  hydraulic  limestone.  These  rocks,  however,  exhibit  but  few  fossils. 
The  dip  and  strike  are  variable,  but  generally  about  east  and  west 
magnetic,  and  the  dip  is  also  irregular,  but  almost  always  to  the  south¬ 
west,  and  at  almost  every  angle  from  nearly  horizontal  to  vertical ; 
the  strike  is  nearly  parallel  with  the  line  of  the  Straits.  Hear  the 
upper  limit  of  the  Cretaceous,  are  sandstones  very  like  those  of  Monte 
Diablo  which  accompany  the  coal,  and  they  contain  a  considerable 
quantity  of  carbonaceous  matter,  but  no  regular  coal-bed,  so  far  as  yet 
discovered.  Hear  these  carbonaceous  strata,  and  above  them,  is  a 
narrow  belt,  partly  altered  and  folded,  and  from  one  hundred  and  fifty 
to  two  hundred  feet  in  width.  The  Rodeo  Valley  marks  the  limit  of 
the  Cretaceous,  going  west  from  Martinez,  the  Tertiary  succeeding  in 
that  direction,  and  resting  conformably  on  the  strata  beneath,  and 
having  the  same  general  southwestern  dip.  South  of  Martinez  the 
Cretaceous  strata  have  a  higher  dip,  but  in  the  same  direction. 

Southwest  of  the  Rodeo  Valley  lies  a  broad  belt  of  Tertiary  rocks, 
which  extends  from  San  Pablo  Bay  to  Amador  Valley,  forming  the 
mass  of  the  Contra  Costa  Hills,  for  a  distance  of  about  thirty-five  miles 
northwest  and  southeast,  and  having  a  breadth  of  from  six  to  eight 
miles.  The  rocks  are  chiefly  sandstones,  and  in  places  highly  fossili- 
ferous.  San  Pablo  Creek  heads  in  this  belt,  and  flows  between  two 
parallel  ridges,  in  the  line  of  the  strike  of  the  rocks.  On  the  west  side 


CONTRA  COSTA  HILLS. 


13 


of  the  creek,  about  four  miles  a  little  south  of  east  from  San  Pablo,  the 
rocks  contain  considerable  bituminous  matter,  and  a  well  had  been 
bored  here  in  1862  to  the  depth  of  eighty-seven  feet,  at  which  point  oil 
was  struck,  which  it  was  proposed  to  purify  by  distillation,  and  works 
were  erected  for  this  purpose,  as  also  to  obtain  oil  from  the  highly 
saturated  sandstone.*  At  these  springs  the  rock  has  a  high  dip  north¬ 
east  ;  hut  a  mile  farther  northwest  it  dips  to  the  southwest,  while  the 
hills  in  the  vicinity  are  too  deeply  covered  by  soil  and  decomposed 
rock  to  admit  of  the  general  position  of  the  strata  being  determined 
satisfactorily. 

To  the  north  of  San  Pablo  are  low  hills  of  very  recent  strata,  which 
are  nearly  horizontal  and  which  rest  unconformably  on  the  edges  of 
the  Tertiary.  Whether  these  beds  contain  any  extinct  species  of  shells 
has  not  yet  been  determined ;  at  all  events,  they  are  no  older  than 
the  Post  Pliocene. 

In  the  valleys  between  San  Pablo  and  Walnut  Creeks,  many  sections 
made  by  the  rains  of  1861-62  in  the  superficial  detritus  were  observed. 
The  beds  are  horizontally  stratified,  and  made  up  of  light  and  darker- 
colored  materials,  the  lighter  ones  being  darker  near  their  upper  sur¬ 
faces,  and  growing  lighter  downwards  to  the  depth  of  from  six  to 
twelve  inches  ;  as  beds  usually  do  when  acquiring  a  color  from  decaying 
vegetable  substances.  This  would  indicate  that  the  rate  of  deposition 
of  this  detritus  has  been  exceedingly  irregular,  long  periods  having 
sometimes  elapsed  without  much  addition  to  the  detrital  deposits,  and 
then,  again,  a  heavy  mass  of  materials  being  suddenly  spread  over  the 
surface,  just  as  takes  place  at  present  during  a  winter  of  extraordinary 
storms,  like  those  of  1861-62.  The  appearances  indicate  sometimes  a 
heavy  deposit  during  one  year  only ;  at  others,  a  succession  of  them 
for  several  years.  The  same  or  similar  facts  were  observed  at  many 
points  in  the  Coast  Ranges. 

The  whole  range  under  consideration  is  denuded  into  a  great  num¬ 
ber  of  hills  and  valleys,  the  latter  running  parallel  with  the  strike  of 
the  strata,  as  will  be  seen  by  referring  to  the  map.  The  valleys  are 

*  The  quantity  of  oil  obtained  seems  to  have  been  too  small  to  pay,  as  the  work  was 
not  profitable,  and  had  been  discontinued  previous  to  the  oil  excitement  of  1865;  whether 
resumed  or  not  we  have  not  been  informed. 


Section  from  near  Pacheco  to  the  Canada  del  Hambre. 

Length,  four  miles. 


14 


GEOLOGY  OF  THE  COAST  RANGES. 


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excavated  in  the  softer  materials,  and 
are  frequently  drained  by  streams  run¬ 
ning  in  two  opposite  directions,  which 
connect  at  their  sources  by  very  low 
divides,  so  that  one  hardly  recognizes 
the  fact  that  he  is  passing  over  them. 
When  streams  cut  across  the  strike 
of  the  strata,  as  they  occasionally  do, 
the  valleys  become  mere  canons,  or 
narrow  rocky  defiles. 

To  the  southeast  of  Martinez  there 
is  a  good  exhibition  of  the  folding  of 
the  strata  exhibiting  a  synclinal  axis, 
as  will  he  seen  from  the  annexed  sec¬ 
tion  (Fig.  1),  by  Mr.  Gabb,  which 
runs  from  a  point  one  mile  north  of 
Pacheco,  southwest  to  the  Canada  del 
Hambre,  a  distance  of  about  4  miles. 

Walnut  Creek  (Arroyo  de  las  Hueces) 
heads  in  the  divide  between  the  valley 
of  this  name  and  that  of  the  San  Ra¬ 
mon  ;  it  separates  the  Contra  Costa 
Hills  from  the  Monte  Diablo  group 
proper.  High  hills  of  Tertiary  sand¬ 
stone  rise  to  the  west  of  it,  attaining 
an  altitude  of  from  1800  to  2000  feet. 
The  high  group  of  hills  north  of  the 
head  of  the  San  Ramon  is  also  of  sand¬ 
stone,  and  has  about  the  same  eleva¬ 
tion.  The  strike  of  the  strata  here  is 
about  H.  50°  W.  to  H.  55°  W.,  and 
the  dip  65°,  to  the  southwest.  The 
San  Ramon,  heading  in  this  group  of 
hills,  runs  southeast,  then  turns  and 
runs  parallel  with  its  former  course  in 
the  opposite  direction,  having  a  high 


CONTRA  COSTA  HILLS. 


15 


and  steep  range  of  fossiliferous  sandstones  between  the  two  parallel 
portions. 

The  foot-hills  along  the  eastern  base  of  these  higher  ridges  are  of 
strata  very  much  broken,  with  every  possible  dip  and  strike,  the  latter 
frequently  at  right  angles  to  that  of  the  strata  in  the  main  ridge,  and 
standing  vertical.  There  are  indications  of  a  line  of  quite  recent  dis¬ 
turbances  of  the  rocks  through  the  San  Ramon  and  El  Hambre  Creeks, 
which  line  crosses  the  general  direction  of  the  stratification  at  an  angle 
of  35°.  There  are  fissures  in  the  soil  along  the  west  side  of  the  San 
Ramon  Valley,  which  were  formed  during  the  earthquake  of  June, 
1861,  and  which  maybe  considered  as  strengthening  the  probability  of 
the  recent  formation  of  this  valley.  That  extensive  disturbances  have 
taken  place  in  the  Monte  Diablo  chain  within  the  most  recent  geolo¬ 
gical  epoch  will  be  seen  farther  on. 

Rear  the  head-waters  of  the  San  Ramon,  the  hills  of  Tertiary  sand¬ 
stone  rise  to  the  height  of  about  2000  feet;  the  strata  have  a  strike  of 
about  R.  39°  to  41°  W.,  and  they  have  a  high  dip  to  the  southwest. 
The  same  strata,  as  followed  along  a  few  miles  farther  to  the  northwest, 
near  Maragua  Valley,  become  more  nearly  vertical,  and  the  strike 
curves  around  more  to  the  west.  The  same  belt  of  rocks  extends  south¬ 
east  from  the  head  of  the  San  Ramon,  through  the  range  of  hills  west 
of  Amador  Valley,  and  they  have  a  lower  and  more  uniform  north¬ 
westerly  dip.  These  hills  sink  into  the  plain  near  the  eastern  end  of 
the  pass  leading  from  Hayward’s  to  Amador  Valley. 

Rear  the  “  AValnut  Creek  House,”  a  small  patch  of  Cretaceous  occurs, 
extending  over  a  few  acres,  from  which  the  overlying  Tertiary,  form¬ 
ing  the  crown  of  a  low  anticlinal,  has  been  denuded. 

A  belt  of  metamorphic  rock  may  be  traced  along  the  western  side 
of  the  Contra  Costa  Hills,  beginning  near  San  Pablo,  thence  following 
the  west  side  of  Wild  Cat  Creek,  and  appearing  in  a  southeast  direc¬ 
tion  along  the  foot-hills  of  the  range,  for  a  distance  of  about  thirty-five 
miles.  It  generally  forms  a  narrow  belt,  not  over  two  miles  wide,  and 
often  not  half  that ;  but  in  some  places  there  is  more  or  less  metamor- 
pliic  action  observable  over  a  width  of  four  miles.  The  northwestern 
portion  of  this  band  of  altered  rock  curves  to  the  northwest,  and  seems 
to  form  the  isolated  metamorphic  hills  lying  near  the  bay  and  west  of 


16 


GEOLOGY  OF  THE  COAST  RANGES. 


San  Pablo  and  islands  of  similar  rock  in  the  Bay,  apparently  connect¬ 
ing  with  the  range  of  high  hills  which  run  out  at  Point  San  Pedro 
and  extend  back  of  San  Rafael. 

Near  San  Pablo  a  great  variety  of  the  results  of  metamorpliic  action 
may  be  observed ;  as,  for  instance,  in  following  a  line  extending  from 
the  house  of  Y.  Castro  back  to  the  top  of  the  ridge.  The  original 
rock  seems  to  have  been  a  more  or  less  bituminous  slate  or  shale,  and 
patches  of  it  have  almost  entirely  escaped  metamorphism,  while  others 
in  the  immediate  vicinity  are  very  much  altered  and  converted  even 
into  mica  slate.  The  dip  of  the  strata,  when  it  could  be  made  out, 
was  to  the  northeast,  30°  at  the  base  of  the  hill  and  gradually  getting 
higher  towards  the  crest  of  the  ridge,  where  the  metamorphism  is  most 
complete.  Here  the  rock  is  traversed  by  small  quartz  veins,  and  has 
evidently  been  acted  on  by  water  containing  silica  in  solution,  as  it  is 
to  a  large  extent  converted  into  that  mixture  of  ferruginous,  jaspery, 
and  clialcedonic  material,  which  is  so  well  known  as  frequently  con¬ 
taining  cinnabar,  that  we  have  become  accustomed  to  call  it  the 
“  quicksilver  rock.”  Considerable  masses  of  actinolite  have  been 
found  lying  on  the  surface  in  this  vicinity,  evidently  derived  from  the 
rocks  of  this  ridge.  The  specimens  resemble  exactly  those  obtained 
from  the  very  much  older  metamorpliic  rocks  of  New  England. 

The  widest  and  highest  portion  of  this  metamorpliic  belt  lies  near 
the  pass  leading  from  Oakland  to  La  Fayette,  the  summit  of  which  is 
1311  feet  above  high  tide.  About  a  hundred  rods  west  of  the  summit 
metamorpliic  slates  stand  vertical,  having  a  close  lithological  resem¬ 
blance  to  rocks  elsewhere  known  to  belong  to  the  Cretaceous  system ; 
a  short  distance  northwest  they  have  a  high  dip  to  the  northeast.  A 
sharp  ridge,  half  a  mile  in  a  direction  N.  32°  W.  from  the  “  Summit 
House,”  is  of  hard  metamorphic  sandstone,  of  which  the  strike  is  N. 
64°  AY.,  but  curving  more  to  the  south  as  we  go  southward ;  the  dip 
is  to  the  northeast,  about  70°  in  amount.  Hand  specimens  of  this 
rock  have  a  very  trappean  look;  but  they  appear  to  be  of  metamorphic 
origin. 

About  one  mile  farther  north  is  the  highest  point  north  of  the  pass, 
called  on  our  map  “  Rocky  Mound;”  it  is  1921  feet  high,  forming  a 
rounded  hill,  having  a  distinct  stratification,  although  very  trappean  in 


CONTRA  COSTA  HILLS. 


17 


its  appearance,  and  a  dip  to  the  northeast.  Between  this  point  and 
the  ridge  spoken  of  in  the  last  paragraph,  there  is  a  mass  of  trappean 
rock,  finely  crystalline  and  very  hard,  in  which  no  planes  of  stratifica¬ 
tion  can  be  observed.  On  the  northeast  of  San  Pablo,  the  unaltered 
strata  rest  on  these  metamorphic  rocks  and  dip  northeast. 

The  ridge  between  Wild  Cat  and  San  Pablo  Creeks  is  made  up  of 
strata  dipping  northeast  from  30°  to  35°,  and  having  a  strike  of  about 
H.  52°  W.  The  north  end  of  this  ridge  is  of  quite  unaltered  strata, 
while  the  southern  portion  is  highly  metamorphosed. 

On  the  east  side  of  Carlisle  Creek,  a  metamorphic  limestone  occurs, 
in  which  all  traces  of  stratification  have  been  obliterated,  the  mass  of 
the  rock  being  traversed  by  veins  of  quartz,  resembling  semi-opal  in 
appearance. 

South  of  the  pass  from  Oakland  to  La  Fayette,  several  high  dome¬ 
shaped  hills  rise,  having  an  elevation  of  about  1850  feet,  made  up  of 
highly  metamorphic  rock  having  a  trappean  aspect,  but  stratified  and 
dipping  northeast.  Intruded  in  this  are  masses  of  rock  which  appear 
to  be  of  decidedly  eruptive  origin,  as  the  metamorphic  strata  are  dis¬ 
placed  in  their  vicinity.  Here,  as  in  many  other  localities  in  California, 
it  is  difficult  to  draw  the  line  between  eruptive  and  sedimentary,  as 
both  have  undergone  extensive  metamorphism  since  their  formation. 

A  short  distance  south  of  the  pass  the  metamorphic  strata  suddenly 
contract  to  about  one  and  a  half  miles  in  width,  an  arm  of  unaltered 
sandstone  and  slates  extending  up  between  'two  branches  of  the  meta¬ 
morphic.  In  this  region  the  slates  are  little  metamorphosed,  appearing 
white  and  easily  decomposed,  although  much  contorted.  Portions  are 
highly  silicious,  but  soft  and  friable,  and,  under  the  name  of  “  kaolin,” 
are  used  to  mix  with  clay  in  making  pottery  at  San  Antonio.  This 
belt  of  slates  and  shales  may  be  traced  southeast  as  far  as  Sunol  Valley, 
beneath  which  they  dip,  rising  again  probably  and  appearing  in  a 
highly  metamorphic  form  in  the  mass  of  the  Mount  Hamilton  Group. 
In  the  places  where  they  are  not  metamorphic  they  have  all  the  litho¬ 
logical  character  of  the  strata  known  to  be  of  Cretaceous  age,  which 
have  been  described  as  occurring  near  Martinez,  and  which  will  be 
noticed  farther  on  as  so  well  developed  near  Monte  Diablo. 

Lying  to  the  west  of  this  are  massive  sandstones,  entirely  unaltered, 

GEOL.  VOT,.  I. — 3 


18 


GEOLOGY  OF  THE  COAST  RANGES. 


which  as  yet  have  furnished  no  fossils,  but  which  are  believed  to  be  ot 
Cretaceous  age.  They  form  an  elevated  ridge,  of  which  the  culminat¬ 
ing  point  is  Redwood  Peak,  1635  feet  above  the  level  of  the  bay.  The 
strike  of  these  sandstones  at  this  point  is  about  X.  69°  W. ;  but  they 
curve  more  to  the  south  on  the  southeastern  side  of  the  ridge.  Their 
usual  dip  is  to  the  northeast;  but  near  Redwood  Point  the  strata  are 
much  broken,  and  three  miles  southeast  they  sometimes  stand  verti¬ 
cally,  or  have  a  very  high  dip  to  the  northeast. 

Beneath  this  mass  of  sandstones,  and  extending  to  the  southwest, 
there  is  a  body  of  coarse  conglomerate,  forming  a  series  of  ridges  of 
considerable  altitude.  Northeast  of  San  Leandro  it  appears  in  the 
range  of  hills  forming  the  eastern  boundary  of  the  San  Antonio  Ranch. 
Ten  or  twelve  miles  farther  to  the  southeast  it  appears  in  Suhol  Peak, 
which  rises  to  an  elevation  of  over  2.000  feet,  on  the  southeast  side  of 
which  it  dips  to  the  southwest.  It  passes  through  the  Suhol  Valley 
and  becomes  a  portion  of  the  great  metamorpliic  belt  of  the  Mount 
Hamilton  Range. 

Although  no  fossils  have  been  found  in  place  in  the  belt  of  slates 
and  shales  alluded  to  above  as  exhibiting  so  well-marked  a  resemblance 
to  rocks  elsewhere  determined  to  be  of  Cretaceous  age,  yet  a  few 
boulders  have  been  picked  up  which  contained  shells  undoubtedly  of 
this  epoch.  A  more  careful  search  will  hardly  fail  to  furnish  some 

farther  evidence  on  this  point.  One  of  these  boulders  was  found  near 

0  * 

the  entrance  of  Suhol  Valley,  in  a  locality  where  it  is  hardly  possible 
that  it  should  have  come  from  any  other  belt  of  rocks  than  that  indi¬ 
cated  above. 

The  metamorphic  band,  before  alluded  to  as  beginning  near  San 
Pablo,  after  narrowing  near  Redwood  Peak,  extends  along  the  western 
slope  of  the  hills,  formii%  the  lower  ridges  at  their  base.  It  does  not, 
however,  form  a  well-defined  belt  parallel  with  the  strike  of  the  strata, 
nor  does  it  appear  to  represent  an  axis  of  elevation.  In  a  section  ex¬ 
amined  from  San  Leandro  across  the  summit  of  Monte  Diablo,  it  was 
seen  conformably  underlying  the  conglomerates  and  sandstones  before 
spoken  of;  but  farther  south  its  relations  to  the  adjacent  rocks  become 
very  obscure,  owing  to  the  almost  entire  obliteration  of  the  lines  of 
stratification  consequent  on  the  increased  metamorphism  of  the  mass. 


MONTE  DIABLO  GROUP. 


19 


As  observed  in  the  foot-hills  of  the  range  between  San  Antonio  and 
Alameda  Creek,  this  metamorphic  belt  has  all  the  characters  which  are 
so  often  exhibited  by  the  altered  Cretaceous  rocks.  Serpentine  is 
abundant  in  it  in  large  irregular  masses,  and  jaspery  slates  like  those 
of  Monte  Diablo.  East  of  San  Antonio  large  patches  are  to  be  seen, 
having  all  the  characters  of  the  quicksilver-bearing  rock  of  New  Al- 
maden  and  New  Idria,  exactly  like  those  noticed  as  occurring  near  San 
Pablo.  Considerable  masses  of  chromic  iron  occur  in  this  position, 
one  of  which  was  formerly  worked  to  some  extent.  Stains  of  copper 
are  not  unfrequent,  and  have  led  to  several  attempts  at  mining,  none 
of  which  have  proved  successful,  or  are  likely  to  repay  the  labor  and 
capital  invested. 

In  the  neighborhood  of  Alameda  Canon  this  metamorphic  belt  ap¬ 
pears  to  be  almost  lost;  but  traces  of  chemical  action,  commenced  and 
partially  completed,  are  exhibited  in  narrow  streaks  visible  among  the 
highly  inclined  and  broken  strata ;  these,  however,  do  not  appear  to 
connect  through  with  the  metamorphic  mass  of  Mount  Hamilton. 


Section  III. — Monte  Diablo  Group. 

Under  this  head,  as  a  subdivision  of  the  Monte  Diablo  Range,  I  shall 
describe  the  region  which  naturally  groups  itself  about  the  dominating 
peak  of  Monte  Diablo;  namely,  all  that  series  of  ridges  and  mountain 
elevations  north  of  Livermore  Valley  and  Corral  Hollow  Pass,  as  far  as 
the  San  Joaquin  River  and  Suisun  Bay,  and  separated  on  the  west  from 
the  Contra  Costa  Hills,  just  described,  by  the  valleys  of  Amador,  San 
Ramon,  and  Walnut  Creek.  For  an  idea  of  both  the  geography  and 
geology  of  the  region  in  question,  the  “  Map  of  the  Region  adjacent  to 
the  Bay  of  San  Francisco”  may  be  consulted;  as  also,  for  a  more  de¬ 
tailed  exhibition  of  a  portion  of  the  group,  the  “  Map  of  the  Vicinity 
of  Monte  Diablo,”  which  is  on  a  scale  of  two  inches  to  the  mile,  and 
which  comprises  an  area  extending  from  four  miles  south  of  Monte 
Diablo  to  twelve  miles  north,  and  having  a  breadth  of  about  eleven 
miles  east  and  west.  This  includes  what,  up  to  this  time,  has  proved 
to  be  by  far  the  most  important  coal-mining  district  in  the  State,  and 


20 


GEOLOGY  OF  THE  COAST  RANGES. 


one  which  on  this  account  was  well  worthy  of  a  representation  on  a 
larger  scale  than  any  other  portion  of  the  Coast  Ranges.  The  region 
about  Monte  Diablo,  moreover,  from  its  convenience  of  access  and 
consequent  facility  of  exploration,  was  at  an  early  stage  in  the  progress 
of  the  Survey  deemed  peculiarly  fitted  to  be  selected  for  a  more  de¬ 
tailed  study  than  could  be  given  to  any  other  considerable  area  of  the 
Coast  Ranges,  and  it  would  be  difficult  to  find  in  any  part  of  the  State 
a  more  interesting  field  for  geological  investigation.  To  the  Survey  it 
has  served  as  a  sort  of  key  for  unlocking  the  stratigraphical  difficulties 
of  the  whole  line  of  upheavals  from  Los  Angeles  to  Clear  Lake,  and 
it  was  here  that  the  existence  of  the  Cretaceous  formation  in  the  State 
was  first  clearly  recognized. 

Monte  Diablo  itself  is  one  of  the  most  conspicuous  and  best  known 
landmarks  in  California.  But  few  persons  in  the  State  can  have  failed 
to  recognize  it  from  some  point  either  of  the  Coast  Ranges  or  of  the 
Sierra  Nevada.  It  is  not  its  great  elevation  which  has  given  it  its  pre¬ 
eminence  among  the  innumerable  peaks  of  the  Coast  Ranges;  it  is  just 
the  height  of  Mount  Bache  near  New  Almaden,  a  point  hardly  known 
by  name  to  those  who  have  not  made  a  special  study  of  the  geography 
of  California,  and  it  is  overtopped  by  Mount  Hamilton,  San  Carlos,  and 
some  nameless  peaks  to  which  no  public  attention  has  ever  been  at¬ 
tracted.  The  reason  why  Monte  Diablo  has  so  marked  a  pre-eminence 
among  the  peaks  of  the  Coast  Ranges  is,  that  it  is,  comparatively  speak- 
ing,  quite  isolated,  especially  on  the  northwest,  north,  and  northeast, 
the  directions  from  which  it  is  most  likely  to  be  seen.  To  the  traveller 
passing  up  Suisun  Bay  and  the  Sacramento  or  San  Joaquin  Rivers,  it 
presents  itself  in  all  its  symmetry  and  grandeur,  rising  directly  from 
the  level  of  the  sea,  and  easily  recognizable  from  a  great  distance  by 
its  double  summit  and  regular  conical  outline,  resembling  that  of  a 
volcano,  which  it  was  generally  supposed  to  be  by  the  early  settlers. 

If  the  mountain  is  made  such  a  conspicuous  landmark  by  its  isolated 
position,  it  becomes  itself,  in  turn,  a  point  from  which  a  vast  area  of  the 
State  may  be  observed  and  studied.  Rising  as  it  does  among  the  Coast 
Ranges,  these  may  be  traced  from  its  summit  from  Mount  Hamilton 
on  the  south  to  unnamed  peaks  in  the  vicinity  of  Clear  Lake  on  the 
north,  and  from  the  plains  of  the  Sacramento  and  the  San  Joaquin  to 


MONTE  DIABLO  GROUP. 


21 


the  Pacific,  east  and  west.  The  great  interior  Valley  of  California  lies 
spread  out  like  a  map,  extending  as  far  as  the  eye  can  reach.  To  the 
cast,  the  view  seems  illimitable,  and  it  is  believed  that  there  are  few,  if 
any  points  on  the  earth’s  surface  from  which  so  extensive  an  area  may 
be  seen  as  from  Monte  Diablo.  This  is  due  to  the  peculiar  form  of  the 
Great  Valley  of  California  and  the  gradual  rise  of  the  Sierra,  which 
brings  higher  and  higher  points  to  view  as  the  distance  becomes  greater. 
The  eye  can  range  over  an  extent  of  400  miles  from  north  to  south,  and 
back  to  the  east,  or  towards  the  summit  of  the  Sierra,  as  far  as  the  crest 
of  this  Range,  the  farthest  northern  point  visible  being  Lassen’s  Butte, 
and  the  most  extreme  southernsome  point  near  Owen’s  Lake  probably, 
thus  affording  a  range  along  this  snow-crested  line  of  mountains  of  over 
300  miles  in  length.  The  whole  area  thus  spread  out  before  the  eye 
can  hardly  be  less  than  40,000  square  miles,  not  much  less  than  that  of 
the  whole  State  of  New  York. 

In  describing  the  geology  of  Monte  Diablo  and  its  surroundings,  it 
will  be  convenient  to  begin  with  the  central  mass  of  the  mountain  itself 


as  a  starting-point.  This  central  mass  is  made  up  of  metamorphic 
rocks ;  it  is  about  six  miles  long,  and  one  and  a  half  miles  in  width, 
and  is  surrounded  on  all  sides  by  entirely  unmetamorphosed  strata.  It 
is  of  an  irregular  crescent  form,  the  concave  side  turned  to  the  north- 
northeast.  The  material  of  which  it  is  composed  is  extremely  variable 
in  its  lithological  character;  but  it  consists  essentially  of  a  central  por¬ 
tion  of  very  hard  metamorphic  sandstone,  containing  considerable  epi- 
dote,  flanked  on  both  sides  by  jaspers,  silicified  shales,  and  slates.  The 
former  constitutes  the  north  peak,  the  latter  the  main  peak,  or  Monte 
Diablo  itself.  The  central  crescent-shaped  mass  of  altered  sandstone 
commences  on  the  northeast,  about  a  mile  and  a  half  in  that  direction 
from  the  north  peak,  sweeps  around  to  the  south  and  passes  with  its 
southern  limit  about  a  quarter  of  a  mile  north  of  the  main  peak,  then 
bends  around  to  the  north  so  as  to  include  the  precipitous  spur  which 
runs  oft'  to  the  northwest,  lying  to  the  east  of  the  head  of  Mitchell’s 
Creek,  and  to  the  highest  point  of  which  we  gave  the  name  of  Eagle 
Point;  this  is  2393  feet  above  the  bay.  Extending  still  farther  to  the 
northwest  it  crosses  the  creek,  and  forms  the  high  north  and  south 
ridge  which  makes  up  the  most  northwesterly  portion  of  the  mountain 


9,9 


GEOLOGY  OF  THE  C(TaST  RANGES. 


mass.  The  southern  extremity  of  this  ridge  we  name  Black  Point; 
the  northern,  Pyramid  Hill:  the  former  is  about  1800  feet  in  elevation, 
the  other  a  little  less.  The  rocks  of  this  ridge  are,  in  part,  an  exceed¬ 
ingly  dark-colored,  tine-grained,  crystalline  material,  destitute  of  traces 
of  stratification  in  the  central  portion  of  the  mass ;  but  which  appears 
to  be  a  metamorphic  sandstone,  although  at  first  sight  it  might  be 
taken  for  an  eruptive  rock.  Its  relations  to  the  surrounding  rocks  in¬ 
dicate  rather  a  metamorphic  than  an  eruptive  origin.  It  would  be 
difficult  to  consider  this  part  of  the  mountain  as  being  of  purely  igneous 
origin,  without  including  with  it  the  rest  of  the  crescentic  mass,  which, 
however,  we  know  from  its  connection  with  the  adjacent  sedimentary 
strata,  and  from  the  fact  that  portions  of  it  have  partially  escaped  the 
metamorphic  action,  to  be  made  up  of  detrital  materials  deposited  from 
water. 

Between  the  north  peak  and  the  main  peak,  or  Monte  Diablo  itself, 
along  the  narrow  ridge  of  a  little  moje  than  a  mile  in  length  which 
connects  the  two  summits,  the  variable  character  of  the  metamorphic 
rock  of  the  mountain  may  be  well  observed.  Portions  of  it  consist  of 
jaspery  material,  or  silicious  slate,  distinctly  stratified ;  these  have  re¬ 
sulted  from  the  metamorphism  of  the  purely  silicious  strata.  Here 
and  there  are  patches  of  imperfect  serpentine,  formed  from  the  more 
argillaceous  sandstones ;  while  in  places  the  rock  becomes  so  highly 
metamorphosed  as  to  be  converted  into  a  well-characterized  mica-slate, 
in  which  numerous  small  garnets  occur,  and  also  zircons  of  minute 
size.  The  north  peak  has  an  elevation  of  3593  feet,  or  263  feet  less 
than  Monte  Diablo  proper.  Here  all  traces  of  stratification  are  lost; 
but  a  careful  examination  of  the  rock,  where  it  is  well  exposed  in  all 
its  relations  to  the  surrounding  strata,  led  irresistibly  to  the  conclusion 
that  it  was  not  of  eruptive  origin.  The  gap  between  the  two  peaks  is 
excavated  in  the  soft,  imperfect  serpentine ;  it  is  about  800  feet  below 
the  summit  of  Monte  Diablo. 

One  of  the  best  points  for  observing  the  gradual  passage  of  the  argil¬ 
laceous  sandstone  into  the  hard  dioritic  or  trappean  rock,  is  along  the 
Hanks  of  the  ridge  of  which  Eagle  Point  is  the  culmination.  The  strata 
here  may  be  traced  in  all  stages  of  passage,  from  the  soft  sandstone  to 


the  hardest  and  most  crystalline  rock,  to  which  in  hand  specimens  an 
eruptive  origin  would  have  readily  been  assigned  by  most  geologists. 

On  the  outside  of  this  great  central  metamorphic  mass,  both  on  the 
north  and  south,  but  not  entirely  surrounding  it,  are  heavy  accumula¬ 
tions  of  jaspery  rock,  one  of  the  most  peculiar  features  of  the  moun¬ 
tain,  and  the  material  of  which  the  culminating  point  itself  is  made  up. 
On  the  north  side  of  the  North  Peak,  these  beds  are  finely  exposed, 
forming  a  lenticular  mass  about  two  miles  long  and  half  a  mile  wide. 
They  have  a  nearly  east  and  west  strike  and  dip  to  the  north.  They 
are  here,  as  elsewhere,  of  a  red  color,  varying  from  a  dull  brick-red  to 
a  brilliant  vermilion  hue.  The  strata  are  usually  thin,  an  inch  being 
about  their  average  thickness,  and  they  are  much  folded  together  and 
twisted.  These  jaspery  strata  on  the  north  side  of  the  North  Peak  do 
not  extend  around  so  as  to  pass  to  the  north  of  the  Eagle  Point  Ridge, 
but  may  be  traced  in  the  ravines  in  which  Bagley  Creek  heads,  passing 
into  the  unaltered  shales  of  undoubted  Cretaceous  age,  in  which  Am¬ 
monites ,  Inoceramus ,  and  other  fossils  have  been  found,  and  which  are 
largely  developed  to  the  north  of  the  mountain  as  well  as  to  the  south. 
On  the  north  side  these  may  be  traced  high  up  into  the  mountain  mass 
along  the  branches  of  the  Arroyo  del  Monte  Diablo.  No  one  making 
an  examination  of  this  part  of  the  mountain  could  doubt  that  these 
jaspers  are  the  result  of  the  alteration  of  the  Cretaceous  shales. 

The  rock  of  the  summit  of  Monte  Diablo  is  the  same  jaspery  mate¬ 
rial,  filled  with  fine  reticulations  of  quartz,  running  through  it  in  every 
direction;  but,  in  some  places,  containing  a  large  amount  of  epidote, 
which  has  been  formed  where  the  shale  contained  originally  more  lime 
than  usual.  The  dip  of  these  metamorphic  strata  is  distinctly  to  the 
north,  and  the  strike  along  the  ridge  leading  to  the  summit  is  nearly 
east  and  west.  At  many  points  on  the  south  side  of  the  mountain  near 
the  summit,  and  for  a  thousand  feet  below,  these  masses  of  contorted 
jaspery  strata  may  be  seen.  At  one  locality,  just  two  miles  west  of  the 
summit,  there  is,  in  a  narrow  ravine,  a  most  beautiful  exposure  of  this 
kind.  The  strata  of  jasper  are  alternately  brilliant  red  and  light  green, 
contrasting  finely  with  each  other,  and  are  folded  together  in  a  manner 
which  is  rendered  very  attractive  from  the  thinness  and  regularity  of 
the  different  layers.  The  strike  here  is,  in  general,  about  N.  54°  YY ., 


24 


GEOLOGY  OF  THE  COAST  RANGES. 


and  the  dip  to  the  north  from  50°  to  70°.  In  tracing  these  strata  to 
the  west,  they  appear  to  give  place  to  other  metamorphic  varieties  of 
rock,  of  which  serpentine  is  the  most  prominent,  and  we  soon  reach 
the  entirely  unaltered  shales  as  on  the  north  side  of  the  mountain. 

Serpentine  is  found,  on  both  the  north  and  south  sides  of  the  moun¬ 
tain,  in  considerable  quantity.  The  largest  mass  is  met  with  on  de¬ 
scending  the  North  Peak  towards  the  north,  where  it  forms  a  lenticular 
deposit  about  two  miles  long  and  half  a  mile  wide,  lying  next  to  the 
jaspery  shales.  It  also  occurs  in  the  gap  between  the  two  summits, 
and  around  the  head  of  the  Arroyo  del  Cerro,  two  and  a  half  miles 
west-nortliwest  of  the  summit.  Here,  as  in  other  localities,  the  serpen¬ 
tine  is  seen  in  every  stage  of  passage  from  the  argillaceous  sandstone 
to  the  perfect  serpentine  itself.  vTlie  boundaries  are  very  irregular  in 
all  these  localities,  especially  on  the  Arroyo  del  Cerro,  where  we  come 
into  the  unaltered  shales  and  sandstones  on  going  a  short  distance  in 
either  direction. 

The  metamorphic  region,  thus  indicated  as  forming  the  central  mass 
of  Monte  Diablo,  covers  about  twenty  square  miles,  and  from  it  a  great 
variety  of  rocks  might  be  obtained.  The  red  and  green  jaspery  rocks, 
however,  are  the  most  characteristic  forms,  and  having  been  here  so 
unmistakably  traced  to  their  origin  as  Cretaceous  shales,  they  have 
been  of  great  service  to  us  in  recognizing  this  formation  in  other  locali- 
•  ties,  where  the  facilities  for  tracing  it  out  in  all  its  connections,  and  of 
determining  its  age  by  fossils  were  less  than  they  were  found  to  be  in 
this  vicinity. 

This  metamorphic  region  has  been,  at  various  times,  assiduously 
explored  for  minerals  and  metalliferous  ores  of  various  kinds.  Gold  is 
reported  to  have  been  obtained  in  small  quantities,  and  was  at  one 
time  the  object  of  expensive  mining  research.  Cinnabar  occurs  at 
several  points,  especially  on  the  northeast  side  of  the  North  Peak,  where 
quite  handsome  specimens  have  been  obtained,  associated  with  the  sili- 
cious  rock  in  which  this  ore  usually  occurs ;  it  is  also  found  on  the 
ridge  of  Eagle  Point.  Copper  ore  has  been  also  the  object  of  much 
excitement  in  this  region,  as  it  is  frequently  found  in  small  quantities, 
and  occasionally  in  rather  large  masses,  in  the  dioritic  variety  of  the 
metamorphic  rock.  In  and  about  Mitchell’s  Canon,  where  this  kind  of 


MONTE  DIABLO  GROUP. 


25 


rock  is  most  developed,  a  considerable  number  of  companies  were  at 
work  in  1862  and  1863;  but  nothing  had  been  discovered  which  could 
properly  be  called  a  regular  vein,  or  worked  with  profit.  It  is  inte¬ 
resting  to  notice,  however,  the  occurrence  of  these  ores  in  a  rock  of  so 
late  a  geological  epoch,  so  evidently  associated  as  they  are  with  the 
existence  of  metamorphic  action  in  this  region. 

Near  the  northwestern  extremity  of  the  metamorphic  mass,  about 
two  miles  northwest  of  the  summit  of  Black  Point,  is  the  largest  mass 
of  travertine  or  calcareous  tufa  which  we  have  yet  observed  in  the 
State.  It  extends  north  and  south  for  a  distance  of  over  half  a  mile, 
forming  low  ridges  running  northwest  and  southeast,  and  having  sand¬ 
stone  both  to  the  north  and  the  south.  Its  width  east  and  west  is  fully 

* 

1000  feet.  It  is  almost  white,  much  of  it  quite  so,  made  up  of  a  very 
pure  carbonate  of  lime,  and  possessing  the  concentrically-aggregated 
structure  so  often  exhibited  by  masses  of  stalagmite.  It  undoubtedly 
owes  its  existence  to  deposition  from  a  hot  spring,  which  once  came  to 
the  surface  at  this  point.  This  deposit  has  been  quarried  and  burned 
for  lime ;  but  was  not  in  use  for  that  purpose  at  the  time  of  our  visit, 
there  not  being  at  this  locality  the  same  facilities  for  fuel  and  transpor¬ 
tation  that  the  lime-kilns  at  Santa  Cruz  have,  so  that  it  could  not  sus¬ 
tain  a  concurrence  with  the  establishmeirUat  that  place. 

It  may  be  mentioned  that  there  are  other  deposits  of  this  calcareous 
material  in  this  region.  The  most  extensive,  next  to  the  one  just 
noticed,  is  on  the  other  side  of  the  San  Ramon  Valley,  near  Mr.  Rus¬ 
sell’s  house,  where  it  forms  a  very  heavy  mass  on  the  side  of  the  hill, 
about  500  feet  above  the  valley. 

Flanking  the  whole  north  side  of  Monte  Diablo  are  unaltered  Creta¬ 
ceous  strata,  having  everywhere  a  northerly  dip,  and  a  general  strike  of 
about  east  and  west  magnetic ;  the  clip  of  the  mass  is  irregular,  in  some 
places  vertical,  but  usually  from  45°  to  35°.  These  Cretaceous  strata 
consist  of  shales  and  sandstones,  the  former  containing  frequent  beds 
of  argillaceous  limestone,  which  are  generally  less  than  a  foot  in  thick¬ 
ness  and  rarely  continuous  for  any  great  length.  The  shales  are  very 
soft  and  disintegrate  easily,  hence  they  are  usually  found  occupying 
valleys  between  the  ridges  of  sandstone,  which  latter  rock  resists  the 
weather  better.  The  valley  at  the  base  of  Monte  Diablo,  which  sepa- 

GEOL.  VOL.  I. — 4 


2G 


GEOLOGY  OF  THE  COAST  RANGES. 


rates  the  mass  of  the  mountain  from  the  hills  farther  north,  in  which 
are  the  coal-mines,  is  occupied  by  these  shales,  which  may  be  traced  in 
the  beds  of  the  two  branches  of  the  Arroyo  del  Monte  Diablo,  which 
unite  at  the  village  of  Clayton. 

The  same  shales  may  be  observed  on  the  south  side  of  the  mountain, 
especially  in  the  Canada  leading  to  Curry’s  house,  and  in  the  ravines 
running  up  to  the  south  from  this  Canada.  As  on  the  north  side,  so 
here,  quite  a  number  of  characteristic  Cretaceous  fossils  were  found  in 
this  belt  of  rocks,  among  which  are  : 


Ammonites  Newberryanus, 

-  Batesii, 

Baculites  chicoensis, 

Fusus  Mathewsonii, 
Amauropsis  alyeata, 
Dentalium  Cooperii, 

-  STRAMTNEUM, 


Venus  yarians, 
Cardium  annulatum, 
Eripiiyla  umbonata, 
Pinna  Brewerii, 
Trigonia  Eyansii, 

CUGULLiEA  TRUNCATA, 

Pecten  operculiformis. 


These  strata,  as  exposed  in  the  bed  of  the  creek  in  Curry’s  Canada, 
have  a  very  irregular  dip,  although  usually  at  a  high  angle,  and  to  the 
southeast,  south,  or  southwest,  near  the  mouth  of  the  Canada.  Near 
Curry’s,  the  dip  is  from  80°#to  vertical,  and  the  strike  nearly  east  and 
west  magnetic. 

Next  above  the  Cretaceous  shales  with  argillaceous  limestones  inter¬ 
calated,  as  just  noticed,  comes  a  very  thick  and  heavy-bedded  mass  of 
sandstones  which,  on  the  north  side  of  the  mountain,  form  the  elevated 
ridge  just  south  of  and  facing  the  coal-mines.  These  sandstones  con¬ 
tain  a  few  Cretaceous  fossils,  such  as  Axinxa ,  Natica ,  and  Dentalium. 

These  Cretaceous  strata  curve  around  to  the  south  as  they  pass  to 
the  east  of  the  mountain,  running  out  into  the  plains  of  the  San  Joaquin 
in  long,  low,  and  almost  exactly  parallel  ridges,  as  will  be  observed  on 
the  Bay  map;  although,  to  the  eye,  the  parallelism  seems  more  extra¬ 
ordinary  than  it  would  appear  to  be  from  an  examination  of  the  map. 
The  counterpart  of  these  Cretaceous  sandstones  of  the  north  side  is 
found  also  on  the  south  side  of  the  mountain,  forming  an  elevated  and 
conspicuous  ridge,  sweeping  around  parallel  with  the  general  strike  of 
the  rocks  in  this  vicinity,  but  not  forming  so  distinct  a  feature  of  the 


MONTE  DIABLO  GROUP. 


27 


topography  of  the  region  as  the  Tertiary  ridge  next  south  of  it.  Its 
culminating  points  rise  to  the  height  of  from  2000  to  2200  feet.  To 
one  of  these  points  or  ridges  where  the  white  soft  sandstone  was,  at 
the  very  summit,  curiously  worn  into  cave-like  hollows,  we  gave  the 
name  of  “  Cave  Point.”  This  is  2070  feet  in  elevation.  Although 
these  sandstones,  in  this  vicinity,  are  very  barren  of  fossils,  enough 
were  found  to  determine  the  fact  that  they  belong  to  the  Cretaceous 
series. 

A  little  south  of  Cave  Point,  in  the  depression  between  that  and  the 
next  ridge  south,  the  sandstone  is  worn  into  curious  tower-like  forms; 
a  group  to  which  we  gave  the  name  of  “  Tower  Rocks,”  is  represented 
in  the  annexed  woodcut.  (Fig.  2.) 


TOWER  ROCKS. 


Coal  has  been  found  in  the  Cretaceous  shales  noticed  above  as  lying 
under  the  sandstone ;  but  the  only  extensive  workable  beds  yet  disco¬ 
vered  are  included  in  the  sandstones  belonging  to  the  upper  part  of  the 
Cretaceous. 

Of  the  Monte  Diablo  coal-beds,  the  only  workable  deposits  of  this 
invaluable  material  yet  discovered  in  the  State,  a  full  account,  illus¬ 
trated  by  sections  and  diagrams,  will  be  given  in  the  volume  devoted 
to  Economical  Geology.  At  the  time  of  our  last  visit  to  this  region, 
in  1862,  the  workings  were  not  sufficiently  advanced  to  enable  us  to 
obtain  all  the  data  desirable  for  forming  an  opinion  of  the  exact  num- 


28 


GEOLOGY  OF  THE  COAST  RANGES. 


ber  and  extent  of  the  beds  which  occur  there,  and  a  detailed  investiga¬ 
tion  was  postponed  until  a  later  period.  A  few  facts  may,  however, 
here  be  stated,  which  will  show  that  these  deposits  are  extremely  in¬ 
teresting  and  of  great  economical  importance  to  the  State,  especially 
as  we  have  reason  to  fear  that  no  coal  of  the  Carboniferous  period 
proper  will  ever  be  found  on  the  Pacific  coast. 

The  coal-mines  in  question  are  situated  on  the  north  side  of  Monte 
Diablo,  about  five  miles  south  of  the  San  Joaquin  River,  by  means  of 
which  water  communication  may  easily  be  had  with  the  Bay  of  San 
Francisco  and  the  Sacramento  Valley.  The  outcrop  of  the  coal-beds 
was  traced  by  us  for  nearly  six  miles,  in  an  easterly  and  westerly  direc¬ 
tion,  from  a  point  about  one  mile  due  north  of  Clayton,  to  near  Coch¬ 
ran’s,  nearly  six  miles  H.  87°  E.  from  that  place.  The  line  of  outcrop 
is  irregular,  curving  to  the  north  in  going  west  from  Cochran’s,  and 
showing  itself  on  the  north  slope  of  the  hills  until  the  Mine  Hill  divide 
is  passed,  when  the  principal  outcrop  is  in  the  face  of  a  high  bluff  facing 
the  south,  as  at  the  Peacock  Mine,  beyond  which  to  the  west  it  is  irre¬ 
gular,  and  can  be  traced  with  difficulty.  There  are  abundant  proofs 
that  the  ground  has  been  uplifted  and  broken,  and  the  coal-beds  dislo¬ 
cated  since  their  deposition,  so  that  only  underground  exploration  will 
render  it  possible  to  fix  with  certainty  their  exact  number,  position, 
and  longitudinal  extent.  This  is  unfortunate,  as  necessarily  leading  to 
considerable  expense  in  fully  developing  the  resources  of  the  region. 

The  dip  of  the  beds  is  highest  at  the  westernmost  mine;  at  the  Pea¬ 
cock  it  was  45°,  as  measured  when  the  mine  was  first  opened ;  towards 
the  eastern  extremity  of  the  outcrop,  as  at  the  Clark  and  Cruikshank 
and  Adams  Mines,  the  inclination  was  from  26°  to  30°,  and  here,  as 
through  the  whole  region,  to  the  north.  At  the  time  of  our  last  visit, 
there  were  known  to  be  two  workable  beds ;  but  whether  the  two  were 
sufficiently  developed  to  admit  of  their  both  being  profitably  worked 
in  any  one  locality  had  not  been  demonstrated.  The  lower  of  the  two, 
or  the  “  Peacock  Vein,”  was  four  feet  thick,  as  opened  by  an  inclined 
shaft,  going  down  at  an  angle  of  33°  to  35°,  and  striking  the  coal  at  a 
depth  of  195  feet  on  the  incline.  Several  small  seams  were  cut  in  this 
shaft,  one  of  which  was  14  inches  in  thickness,  indicating  irregularity 
in  the  deposition  of  the  strata,  and  rendering  probable  the  conclusion, 


MONTE  DIABLO  GROUP. 


29 

+ 

that  at  no  two  points  on  the  line  of  outcrop  will  .the  sections  of  the 
strata  and  the  included  coal-beds  be  found  exactly  the  same,  a  conclu¬ 
sion  also  arrived  at  from  an  inspection  of  the  surface.  In  the  Peacock 
shaft,  the  coal  was  found  to  be  so  much  broken  by  a  dislocation  a  little 
to  the  west,  that  work  was  abandoned,  and  we  are  not  aware  that  it  has 
been  resumed. 

At  the  Cumberland  Mine,  three-fourths  of  a  mile  70°  E.  from  the 
Peacock,  this  vein  was  also  four  feet  thick,  with  a  considerable  thick¬ 
ness  of  dark  shale,  with  much  coaly  matter  in  it,  both  above  and  be¬ 
neath.  The  Black  Diamond  Mine,  a  little  over  a  quarter  of  a  mile  to 
the  east  of  the  Cumberland,  afterwards  purchased  by  the  company 
owning  this  last-mentioned  mine,  showed,  in  1862,  the  bed  of  coal  to 
be  from  three  feet  six  inches  to  four  feet  thick,  averaging  three  feet 
nine  inches.  There  are  several  inches  of  shale  under  the  coal,  and  a 
thin  layer  above.  This  locality  had  only  just  been  opened  when  last 
examined  by  us ;  but  it  has  since  been  extensively  worked. 

At  the  Clark  Mine,  when  first  opened,  the  bed  of  coal  was  three  feet 
six  inches  to  four  feet  two  inches  thick,  and  it  had  a  dip  of  from  24°  to 
26°.  The  roof  was  of  shale  from  six  to  twelve  inches  thick,  and  the 
bottom  of  the  coal  rested  directly  on  the  sandstone.  At  the  Cruikshank 
and  Adams  Mine  the  bed  of  coal  was  two  feet  nine  inches  thick,  dip¬ 
ping  30°,  and  without  clay  or  shale  either  above  or*below. 

Since  our  examination  of  this  region,  many  changes  have  been  made 
in  the  ownership  and  working  of  the  mines,  and  it  is  said  that  six  or 
seven  companies  are  taking  out  coal,  or  making  preparations  for  s6 
doing,  and  the  produce  of  all  the  mines  in  1864  is  given  at  37,453  tons. 
It  is  said  that  the  companies  now  at  work  might  produce  50,000  tons 
a  year  without  difficulty,  if  there  was  a  sufficient  demand  for  it.  And 
this  demand  is  constantly  increasing,  as  the  Monte  Diablo  coal  can  be 
delivered  at  San  Francisco,  and  sold  at  a  profit,  at  a  lower  price  than 
that  from  any  other  locality.  As  soon  as  a  railroad  is  built  to  the  San 
Joaquin,  and  the  proper  arrangements  made  for  shipping  the  coal,  with¬ 
out  handling  it  over  so  many  times  as  is  now  necessary,  it  will  be  deli¬ 
vered  in  much  better  order,  and  at  a  lower  price  than  can  now  be 
done. 

The  quality  of  the  Monte  Diablo  coal  is  such  as  to  adapt  it  for  use  in 


30 


GEOLOGY  OF  THE  COAST  RANGES. 


families  and  on  the  river  steamers.  Like  other  coals  of  a  later  geolo¬ 
gical  period  than  the  true  Carboniferous,  it  contains  considerable  water, 
which  is  driven  off  on  drying  at  the  temperature  of  212°.  It  also  parts 
with  this  moisture,  although  more  slowly,  after  being  taken  from  the 
mine  and  exposed  to  the  ordinary  temperature  of  the  air.  In  thus 
losing  its  moisture,  the  coal  slacks  or  crumbles  to  some  extent.  These 
same  defects,  however,  are  found  in  some  of  the  Carboniferous  coals  of 
the  Mississippi  Valley,  the  percentage  of  water  in  some  samples  of 
Iowa  coal  being  as  great  as  in  some  of  those  from  Monte  Diablo.  In 
other  respects,  the  coals  of  this  region  resemble  the  highly  bituminous 
coals  of  the  true  coal-measures,  as  will  be  seen  from  the  following 
analyses  of  some  of  the  principal  varieties  of  Cretaceous  and  Tertiary 
coals  used  on  the  Pacific  coast,  among  which  specimens  of  the  princi¬ 
pal  Monte  Diablo  mines  may  be  found.  More  complete  analyses  will 
be  given  hereafter. 


1 

Clark  &  Co. 

Black  Diamond. 

Cumberland. 

Peacock. 

Corral  Hollow. 

Bellingham  Bay. 

I 

i 

Nanaimo. 

Coose  Bay. 

O 

w 

< 

s 

m 

Water, . 

13.47 

14.69 

13.84 

14.13 

20.53 

8.39 

2.98 

20.09 

17.54 

• 

Bituminous  substances, 

40.36 

33.89 

40.27 

37.38 

35.62 

33.26 

32.16 

32.59 

35.93 

Fixed  Carbon,  .  .  . 

40.65 

46.84 

44.92 

44.55 

36.35 

45.69 

46.31 

41.98 

43.00 

Ash, . 

5.52 

4.58 

.97 

3.94 

7.50 

12.66 

18.55 

5.34 

3.53 

It  must  be  remarked  that  these  analyses  were  made  in  1861  and 
1862,  and  are  of  specimens  taken  at  no  very  great  depth. 

The  Monte  Diablo  coals  all  contain  about  the  same  amount  of  water, 
namely  about  fourteen  per  cent.,  while  the  Bellingham  Bay  and  the 
Nanaimo  coals  have  much  less,  the  Nanaimo  less  than  three  per  cent. ; 
yet  these  coals  are  of  the  same  geological  age  as  those  of  Monte  Diablo; 
hence  it  may  prove  that  the  quantity  of  moisture  in  the  California  Cre¬ 
taceous  coal  will  be  diminished  as  the  mines  are  worked  to  a  greater 
depth.  The  Monte  Diablo  coal  is  remarkably  free  from  mineral  and 
stony  matter,  one  specimen  leaving  less  than  one  per  cent,  of  ash, 


MONTE  DIABLO  GROUP. 


31 


and  no  other  as  much  as  six.  In  this  respect  they  are  equal  to  any 
coals  in  the  world,  and  greatly  superior  to  those  of  Nanaimo  and  Bel¬ 
lingham  Bay.  They  are  also  hut  little  contaminated  with  sulphur,  at 
least  the  better  qualities  are  comparatively  free  from  this  deleterious 
material.* 

The  exact  limit  of  demarcation  between  the  Cretaceous  and  the  Ter¬ 
tiary,  in  this  vicinity,  has  not  been  exactly  made  out.  Resting  on  the 
coal-bearing  strata  above  described,  there  is  a  heavy  mass  of  sandstone, 
with  some  shales  interstratified,  which,  however,  are  more  silicious 
than  the  truly  Cretaceous  beds  of  otherwise  similar  character.  These 
beds  appear  to  be  beds  of  passage  between  the  Cretaceous  and  the  Ter¬ 
tiary  ;  but  fossils  are  so  extremely  rare  in  them  that  it  is  not  easy  to 
come  at  their  precise  relations.  They  hold  the  position  which  should 
be  occupied  by  the  Eocene  Tertiary ;  but  have  yielded  no  forms  recog¬ 
nized  elsewhere  as  of  this  particular  age.  This  mass  of  sandstones 
occupies,  on  the  north  side  of  the  mountain,  a  considerable  width  on 
the  surface,  apparently  not  less  than  a  mile,  to  the  north  of  Mine  Hill. 
On  the  south  side  it  appears  less  distinctly  marked ;  in  fact,  there 
seems  to  be  but  little  room  for  this  body  of  strata  between  those  of 
undoubted  Cretaceous  age  at  Tower  Rocks,  and  the  high  ridge  of 
Miocene  Tertiary  directly  south  of  it. 

Rocks  of  both  Pliocene  and  Miocene  age  are  extensively  developed 
to  the  north  of  the  strata  just  spoken  of,  on  the  northern  slope  of 
the  range  in  which  are  the  coal-mines.  Those  which  we  refer  to  the 
Miocene  division  of  the  Tertiary  consist  chiefly  of  sandstones,  which 
are  very  heavy-bedded  towards  the  base  of  this  part  of  the  series. 
They  are  succeeded  above  by  thinner  and  more  fossiliferous  strata, 
which  not  only  contain  large  numbers  of  marine  fossils,  but  also  im¬ 
pressions  of  leaves  and  considerable  fossil  wood,  the  latter  silicified 
and  lying  upon  the  surface,  the  rock  having  decomposed  around  it. 
These  upper  strata  are  referred  by  Mr.  Gabb  to  the  Pliocene  division 
of  the  Tertiary,  from  a  consideration  of  the  number  of  living  species 
which  they  contain,  as  well  as  from  their  stratigrapliical  position.  The 

*  The  coals  and  coal-deposits  of  the  Pacific  coast  will  be  fully  investigated  and  reported 
on,  in  the  volume  of  this  Report  devoted  to  Economical  Geology. 


32 


GEOLOGY  OF  THE  COAST  RANGES. 


following  species  were  collected,  from  this  group  of  strata,  near  the 
east  end  of  Kirker’s  Pass:  * 

Trophon  PONDEROSUS, 

Purpura  canaliculata, 

Littorina  planaxis, 

-  Remondii, 

Serpulorbis,  sp.  undt., 

COLUMBELLA  RlCHTHOFENI, 

ZlRPHiEA  DENTATA, 

SOLEN  SICARIUS, 

Gari  ALATA, 

Standella  PLANULATA, 

Resting  upon  these  are  strata  of  volcanic  materials,  such  as  ashes 
and  pumice,  which  have  evidently  been  ejected  or  w ashed  into  water  and 
deposited  in  a  stratified  condition.  These  beds  to  the  west  of  Kirker’s 
Pass  have  a  thickness  of  several  hundred  feet,  and  rise  into  considera¬ 
ble  hills.  Their  dip  is  usually  about  25°  to  30° ;  but,  in  some  places, 
they  are  elevated  at  as  great  an  angle  as  50°.  Their  strike  is  also 
somewhat  irregular,  and  they  form  a  series  of  rounded  and  bare  hills, 

stretching  along  near  the  edge  of  the  San  Joaquin  plain. 

% 

Above  the  sedimentary  volcanic  beds  just  noticed  are  beds  of  gravel 
and  loose  materials,  probably  of  Post-Pliocene  age,  which  also  have  a 
considerable  but  variable  thickness,  and  which  pass  gradually  into  the 
modern  deposits  of  the  valley.  All  these  strata,  from  the  Cretaceous 
up  to  the  Post-Pliocene,  appear  to  be  perfectly  conformable  with  each 
other,  and  they  all  have  a  northerly  dip,  although  it  is  variable  in 
amount. 

The  Pass  called  after  Mr.  Livermore,  an  old  settler  in  the  valley,  is 
on  the  west  side  of  the  eastern  division  of  the  Monte  Diablo  Group, 
and  about  sixteen  miles  southeast  of  the  summit  of  the  mountain,  and 
here  the  chain  is  more  completely  broken  through  than  at  any  other 
point  in  its  whole  extent;  this  Pass  has,  for  that  reason,  been  selected 
for  the  passage  of  a  railroad  from  San  Jos6  to  Stockton,  for  which  the 
preliminary  surveys  have  been  made,  and  which  is  now  in  process  of 


Tapes  tenerrima, 

-  straminea, 

Saxidomus  aratus, 
Dosinia  ponderosa, 
Gyrene  Californica, 
Pachycardium  Gabbii, 
Mytilus  Californianus, 
Pallium  crassicardo, 
Ostrea  Bourgeoisie 


*  For  a  description  of  such  of  these  as  are  new,  see  Palaeontology,  Volume  II,  of  the 
Report  of  the  California  Survey. 


MONTE  DIABLO  GROUP. 


33 


construction.  The  western  division  of  the  chain,  the  Contra  Costa 
Hills,  already  described  in  this  chapter,  are  entirely  broken  through  by 
the  canon  through  which  the  Alameda  Creek,  which  drains  a  Thrge 
region  in  the  interior  of  the  range,  finds  its  way  to  the  Bay  of  San 
Francisco.  This  canon,  therefore,  in  connection  with  the  Livermore 
Pass,  furnishes  a  good  and  easy  route  for  a  railroad  entirely  across  from 
the  bay  to  the  plains  of  the  San  Joaquin ;  it  is,  indeed,  the  only  feasible 
one.  As  we  issue  from  the  Alameda  Canon,  going  towards  Livermore 
Pass,  we  come  into  a  valley  or  plain  some  twelve  miles  in  length,  but 
of  irregular  width,  which  extends  to  the  western  entrance  of  the  pass. 
The  western  portion  of  this  is  called  “  Amador  Valley ;”  the  eastern, 
“ Livermore  Valley.”  These  valleys  are  formed  by  the  sinking  down 
of  the  Tertiary  ranges  of  hills  which  lie  along  the  southwestern  slope 
of  Monte  Diablo.  The  portion  of  the  range  which  continues  to  the 
southward,  and  which  connects  the  Monte  Diablo  group  with  the  Mount 

Hamilton  group,  and  over  which  the  Livermore  and  Corral  Hollow 

• 

passes  cross,  is  made  up  of  a  very  irregular  belt  of  hills  about  ten  or 
twelve  miles  wide,  most  elaborately  wrought  out  by  denudation  into 
a  labyrinth  of  ridges  and  canons,  the  minute  exhibition  of  whose  de¬ 
tails  would  require  a  map  on  a  very  large  scale.  These  ridges  are 
nearly  destitute  of  trees,  with  but  a  scanty  supply  of  feed,  in  the  shape 
of  grass  or  forage,  and  poorly  provided  with  water,  what  there  is^being 
generally  alkaline.  The  hills  in  the  vicinity  of  the  pass  are  seldom 
over  1200  feet  high,  but  they  rise  higher  a  little  farther  north,  and 
“  Bushy  Knob,”  or  “  Las  Cuevas,”  may  be  considered  as  the  culmi¬ 
nating  point  of  this  division  of  the  group;  it  is  1742  feet  above  tide¬ 
water. 

The  pass  itself  is,  according  to  the  Pacific  Railroad  Surveys,  481  feet 
high  at  its  western  entrance,  and  686  feet  at  its  summit;  by  our  mea¬ 
surement,  the  eastern  entrance,  at  “  Zimmerman’s  Mountain  House 
(Camp  60),  is  223  feet  above  the  sea. 

The  rocks  near  the  pass  are  sandstones,  which  are  soft  and  easily  dis¬ 
integrated.  They  are  of  Tertiary  age,  but  contain  few  fossils.  Along 
the  eastern  side  of  the  range  the  dip  is  to  the  northeast,  and  on  the 
western  side  it  is  in  an  opposite  direction,  there  being  a  low  axis  run¬ 
ning;  through,  the  region  from  southeast  to  northwest,  and  passing  a 

OEOT,.  VOT..  T. — 5 


34 


GEOLOGY  OF  THE  COAST  RANGES. 


little  to  the  east  of  Bushy  Ivnob.  The  dip  in  both  directions  is  quite 
small,  in  keeping  with  the  comparatively  small  elevation  of  this  portion 
of  the  chain.  At  Bushy  Knob  it  was  only  15°,  the  direction  of  the 
strata  being  H.  69°  W. 

South  of  Livermore  Valley  the  hills  rise  in  altitude,  but  exhibit  in  the 
main  the  same  features  as  on  the  other  side,  until  we  approach  Corral 
Hollow.  They  are  rounded  in  outline,  and  the  rock  is  rarely  seen, 
except  in  the  canons.  As  we  reach  Corral  Hollow  we  find  the  strata 
more  disturbed,  and  all  the  indications  of  an  approach  to  another  great 
metamorphic  centre. 

The  pass  or  canon  usually  known  as  Corral  Hollow  extends  back 
from  the  San  Joaquin  plain  and  opens  into  Livermore  Valley ;  it  crosses 
the  hills  about  ten  miles  south  of  the  Livermore  Pass,  but  is  more 
elevated  than  that,  and  traverses  a  greater  variety  of  rocks,  as  it  inter¬ 
sects  both  the  altered  and  the  unaltered  Cretaceous  strata  in  its  upper 
portion. 

This  upper  region  of  the  pass,  which  has  a  northwest  and  southeast 
direction,  is  a  deep,  precipitous  canon,  extending  across  to  the  Liver¬ 
more  Valley  from  the  bend  in  Corral  Hollow  Creek.  This  creek,  as 
is  so  often  the  case  with  the  streams  in  this  region,  runs  towards  the 
northwest,  parallel  with  the  stratification,  for  a  considerable  distance,  and 
then  turns  suddenly,  and,  crossing  the  strata,  runs  at  right  angles  to  its 
former  course,  The  change  in  direction  is  just  at  the  point  where  the 
unaltered  strata  are  intersected.  The  general  strike  of  the  strata  in 
this  region  is  nearly  magnetic  east  and  west,  or  H.  70°  to  75°  W. ;  the 
dip  is  usually  to  the  north,  at  a  pretty  high  angle,  but  very  variable. 
The  metamorphic  region  in  which  Corral  Hollow  Creek  heads  will  be 
noticed  farther  on,  as  it  forms  a  part  of  the  Mount  Hamilton  group. 
The  division  between  the  metamorphic  and  unaltered  rocks  in  the 
angle  of  the  creek  is  well  marked  and  easily  recognized  at  a  distance, 
from  the  varied  character  which  the  different  rocks  give  to  the  land¬ 
scape.  The  metamorphic  hills  are  covered  with  a  darker  and  thinner 
soil,  and  are  more  bountifully  supplied  with  trees,  especially  the  Quer- 
cus  agrifolia  and  Q.  Garrgana ,  while  the  outlines  of  the  ridges  are 
sharper  and  the  outcrops  of  rock  more  numerous.  Kear  the  junction 
with  the  unaltered  strata,  the  metamorphosed  beds  preserve  their  origi- 


MONTE  DIABLO  GROUP. 


lying  beds  of  rock,  which  have  undergone  no  change.  These  meta- 
morphic  rocks  are  of  Cretaceous  age,  and  are  identical  in  appearance 
with  the  jaspery  rocks  noticed  as  occurring  so  abundantly  near  Monte 
Diablo.  The  jasper  bands  are  from  a  fourth  of  an  inch  to  several 
inches  in  thickness,  sometimes  very  much  contorted  and  of  various 
colors — red,  rose-colored,  green,  gray,  and  white;  the  whole  present¬ 
ing,  especially  on  the  weathered  surfaces,  the  most  brilliant  and  beau¬ 
tiful  appearance.  There  are  also  reticulations  of  quartz  crossing  the 
mass  in  small,  irregular  veins  and  threads,  such  as  have  already  been 
described  as  occurring  near  Monte  Diablo,  forming  the  peculiar  rock 
which  we  have  followed  from  this  region  north  as  far  as  Clear  Lake. 
Serpentine  is  also  abundantly  distributed  through  this  metamorphic 
region. 

Between  the  metamorphic  and  the  Tertiary  there  is  a  narrow  belt  of 
unaltered  rock,  of  Cretaceous  age,  the  metamorphic  action  not  having 
penetrated  through  the  whole  mass  of  the  strata*  But  few  perfect  fos¬ 
sils  were  found  in  these  unaltered  rocks,  and  these  were  distinct  from 
any  obtained  elsewhere  in  the  Cretaceous,  to  which  formation,  how¬ 
ever,  they  were  referred,  with  some  doubt,  by  Mr.  Gabb,  who  described 
two  species  from  this  locality,  namely,  Cyprinella  tenuis  and  Corbula 
primorsct ;  besides  these,  Anomia  and  Mytilus  were  observed,  as  also 
three  other  bivalves,  too  imperfect  to  be  referred  with  certainty  to  any 
genus.  Mr.  Gabb  considers  that  these  fossils,  which  overlie  rocks 
known  to  be  of  Cretaceous  age,  and  which  dip  under  the  Miocene  Ter¬ 
tiary,  may  probably  prove  to  belong  to  a  bracldsh-Water  deposit  of  the 
Cretaceous,  although  it  is  possible  that  the  formation  in  which  they 
occur  may  represent  the  Eocene  division  of  the  Tertiary. 

The  dip  and  strike  of  these  unaltered  rocks  are  variable,  but  they 
usually  incline  at  a  pretty  high  angle  to  the  north.  Two  sections  were 
made  across  the  valley  in  this  region,  which  will  serve  to  show  the 
position  of  the  strata  and  also  of  the  coal-beds,  which  are  found  here, 
and  which  have  been  worked  to  some  extent.  The  tirst  crosses  Corral 
Hollow  at  the  “  Pacific  Mine,”  and  runs  H.  20°  E.;  it  represents  a 
length  of  five  miles,  and  is  on  an  equal  scale  of  horizontal  and  vertical 
distances.  The  other  one  crosses  at  the  Almaden  Mine,  and  is  of  about 


* 


Fig.  3. 

Section  across  Corral  Hollow  at  the  Pacific  Mine. 

Direction  N.  20°  E. ;  length  5  miles;  scale  of  heights  and  distances  equal. 


GEOLOGY  OF  THE  COAST  RANGES. 


36 


m 


the  same  length  as  the  other.  On  com¬ 
paring  these  two  sections  it  will  be  seen 
at  once  how  great  a  disturbance  of  the 
rocks  has  taken  place  in  this  region r 
within  so  short  a  distance,  as  the  whole 
series  of  sandstones  on  the  north  side  of 
the  hollow  lias  in  one.  section  a  posi¬ 
tion  exactly  the  reverse  of  that  in  the 
other.  In  the  section  at  the  Pacific 
Mine  the  mass  of  unaltered  strata  north 
of  the  hollow  lies  nearly  conformable 
with  the  metamorphic;  and,  like  that, 
dips  to  the  north  for  a  distance  of  a  mile 
and  a  half;  then  we  have  a  mass  of  dis¬ 
turbed  strata  and  a  reversal  of  the  dip. 
In  the  Almaden  Mine  section  the  rever¬ 
sal  of  the  dip  takes  place  in  the  strata 
immediately  connected  with  the  coal, 
which  of  course  has  an  unfavorable  in- 
fiuenee  on  the  working  of  the  bed.  In¬ 
deed,  the  disturbances  in  this  district 
are  so  extensive  that  it  is  to  be  feared 
these  coal-beds  will  not  be  made  avail¬ 
able  ;  and  up  to  the  present  time,  at 
least,  they  have  not  been,  although  the 
quality  of  the  coal  is  good  as  compared 
with  other  Pacific  coast  coals,  and  the 
thickness  of  the  beds  sufficient  for  pro¬ 
fitable  working,  if  they  had  not  been  so 
much  disturbed  by  the  movements  of  the 
strata.* 

From  Mr.  Brewer’s  notes  the  follow¬ 
ing  notice  of  these  mines  is  taken.  The 
Pacific  Mine  is  situated  near  the  upper 

*  For  an  analysis  of  the  Corral  Hollow  coal,  see 
page  30. 


MONTE  DIABLO  GROUP. 


37 


curve  of  the  stream,  on  the  south  side, 
about  nine  miles  from  the  mouth  of  the 
valley,  and  950  feet  above  the  sea.  The 
stratum  of  coal  is  in  sandstones  and 
shales ;  the  strike  is  H.  80°  W.,  and  the 
dip  50°  to  70°  to  the  north.  The  strata 
are  much  broken,  and  frequent  slips  and 
faults  occur,  while  the  dip  is  quite  vari¬ 
able.  A  drift  cuts  the  bed  from  the 
lower  side  and  follows  it  for  a  distance 
of  three  or  four  hundred  feet.  The  bed 
shows  at  its  eastern  end  a  thickness  of 
fifty  inches  of  workable  coal.  It  was 
stated  that,  up  to  October  15th,  1861, 
from  two  hundred  to  four  hundred  tons 
had  been  mined  here.  When  visited 
again  in  1862,  but  little  farther  work 
had  been  done  here.  The  drift  had 
been  extended  a  few  feet,  and  the  thick¬ 
ness  of  the  coal  was  found  to  be  sixty- 
six  inches.  Many  facts  were  noticed, 
showing  how  great  a  disturbance  had 
taken  place  here.  In  the  strata  beneath 
the  coal  are  many  angular  fragments  of 
the  coal  itself,  which  appear  to  have 
slipped  out  of  place  and  to  have  been 
caught  between  the  strata  while  under¬ 
going  these  convulsions,  which  in  one 
place  have  cut  the  seam  entirely  oft*  and 
brought  it  squarely  up  against  the 
broken  edge  of  the  sandstone. 

The  Coast  Range  Company  was  the 

0 

first  one  to  mine  in  this  district.  Their 
shaft  is  one  and  a  half  miles  below  that 
of  the  Pacific  Company,  in  the  bottom  of 
the  valley,  on  the  south  side.  The  coal- 
seam  was  perpendicular,  and  a  shaft  was 


Sea  level.  k  h  g  fed  c 

a.  Shaft  on  coal-seam,  dipping  S.  80°  to  85°.  b.  Thin  seam  of  coal,  nearly  vertical,  with  sandstones  on  each  side.  c.  Metamorphic  rock,  with  northern 
dip.  d.  Serpentine,  e.  Metamorphic  slates  and  sandstones,  f.  Unaltered  sandstones  dipping  north,  g.  Unaltered  sandstones  dipping  south,  12°  to  15°. 
h.  Locality  of  fossil  leaves,  k.  Unaltered  sandstones. 


GEOLOGY  OF  THE  COAST  RANGES. 


sunk  in  it  to  the  depth  of  100  feet;  but  little  good  coal  was  found,  and 
it  is  now  abandoned. 

Some  explorations  and  attempts  at  mining  at  the  Almaden  Com¬ 
pany’s,  on  the  south  side  of  the  canon,  gave  equally  discouraging  re¬ 
sults,  the  strata  being  much  broken,  so  that  the  bed  could  not  be  fol¬ 
lowed  continuously  in  the  shafts,  one  of  which  had  been  sunk  to  the 
depth  of  one  hundred  and  fifty  feet  in  1861.  In  this  shaft,  as  will  be 
noticed  on  the  section,  the  strata  dip  to  the  south  at  a  high  angle, 
there  being  a  complete  overturn  of  the  strata  here.  The  bed  of  coal 
exposed  in  this  shaft  was  about  two  feet  thick,  and  of  good  quality, 
although  much  crushed  and  therefore  easily  disintegrated.  As  far  as 
can  be  ascertained,  no  coal  has  been  shipped  from  these  mines  of  late, 
and  they  are  probably  abandoned.  Unless  the  quality  and  quantity  of 
the  Corral  Hollow  coal  were  quite  superior,  it  would  be  impossible  for 
it  to  come  in  competition  with  the  product  of  the  Monte  Diablo  mines, 
the  latter  being  so  much  more  favorably  situated  with  reference  to  a 
market. 

To  the  north  of  the  belt  of  Cretaceous  strata  just  described,  there  is 
an  extensive  region  of  Tertiary  hills,  extending  towards  Livermore’s 
Pass.  The  highest  of  these  are  from  2400  to  2500  feet  in  altitude;  the 
highest  point  measured  was  two  and  a  half  miles  north  of  the  Pacific 
Mine,  and  its  altitude  was  found  to  be  2198  feet.  The  rock  in  these  hills 
is  deeply  covered  with  soil,  but  is  sufficiently  exposed  in  the  canons  to 
show  that  it  has  a  very  variable  strike  and  dip,  being  much  affected  by 
the  fault  or  disturbance  which  passes  through  Corral  Hollow.  On  the 
hills  north  of  the  mines  there  are  several  localities  of  the  large  fossil 
oysters  ( Ostrea  Titan),  where  these  occur  in  great  numbers. 

About  one  mile  north  of  Camp  61,  the  impressions  of  leaves  and 
silicified  wood  were  found  in  great  abundance  in  a  soft  sandstone,  sup¬ 
posed  to  be  of  Pliocene  age.  The  strata  had  a  dip  to  the  southeast, 
and  the  leaves  were  chiefly  found  in  a  stratum  about  two  feet  thick. 
They  were  very  pumerous  and  beautifully  preserved,  and  represented 
several  genera  of  deciduous  trees.  These  leaves  will  be  fully  described 
in  the  second  volume  of  the  Palaeontology  of  this  Report.  In  one  case  a 
stump  was  found  still  upright,  its  roots  in  the  leaf-bearing  stratum,  and 
its  top  projecting  into  that  next  above.  These  indications  of  a  terrestrial 


MOUNT  HAMILTON  GROUP. 


39 


Flora  were  observed  over  an  area  of  several  square  miles,  but  the  exact 
relations  of  the  strata  to  the  oyster-beds  could  not  be  made  out,  owing 
to  the  fact  that  the  exposures  of  the  rocks  are  so  poor  in  this  region. 


Section  IV. — Mount  Hamilton  Group. 

The  region  south  of  Corral  Hollow,  as  far  as  Pacheco’s  Pass,  may, 
as  has  already  been  stated,  be  conveniently  considered  as  a  subdivision 
of  the  Monte  Diablo  Range.  The  separation  of  it,  for  the  purpose  of 
geological  description,  from  the  Monte  Diablo  and  San  Carlos  subdivi¬ 
sions  of  the  range  on  the  north  and  the  south  respectively,  although 
somewhat  artificml ,  is  not  wholly  unfounded.  The  great  break  to  the 
north  in  the  chain,  at  and  near  Corral  Hollow  and  Livermore’s  Pass, 
caused  by  the  absence  of  metamorphism  and  the  easy  denudation  of 
the  soft  sandstones  of  Tertiary  age,  makes  a  well-marked  line  on  that 
side,  and  south  from  there  to  Pacheco’s  Pass  the  mass  of  ranges  forms 
one  connected  whole,  unbroken  by  any  depression.  It  is  a  great  area, 
fifty  miles  long  by  thirty  wide,  entirely  covered  by  mountains,  many  of 
them  very  high  and  rough,  scantily  supplied  with  water,  and  as  little 
traversed,  even  by  hunter  or  explorer,  as  any  portion  of  the  State.  JSTo 
map  at  all  approaching  to  accuracy  or  even  giving  the  outline  of  its  geo¬ 
graphy  lias  ever  appeared.  The  explorations  of  the  Geological  Survey 
have  not  extended  all  over  this  forbidding  region,  yet  our  parties  have 
penetrated  it  on  all  sides,  and  especially  from  the  eastern, — Messrs. 
Brewer,  Gabb,  and  Hoffmann  having  devoted  about  six  weeks  of  the 
early  season  of  1862  to  exploring  it  on  that  side,  returning  through 
Pacheco’s  Pass,  and  making  several  excursions  into  it  from  the  western 
ed^e  of  the  mountains. 

A  portion  of  the  geography  of  this  region  is  to  be  found  on  the  Bay 
Map,  namely  the  northwestern  corner,  as  far  south  as  Mqunt  Hamil¬ 
ton  ;  but  the  connected  geography  of  the  whole  district  will  not  be 
given  until  the  publication  of  our  Map  of  Central  California,  which  is 
now  in  preparation. 

The  description  of  this  district  will  be  best  entered  into  by  taking 


# 


40  GEOLOGY  OF  THE  COAST  RANGES. 

up  the  region  adjacent  to  Corral  Hollow  and  proceeding  southward 
along  its  eastern  edge,  following  Mr.  Brewer’s  notes  chiefly. 

Lone  Tree  Canon  lies  about  seven  miles  southeast  of  Corral  Hollow, 
the  stream  or  creek  of  the  same  name  rising  in  several  canons  in  the 
metamorphic  rocks,  about  ten  miles  back  from  the  plain.  The  lower 
four  miles  of  this  canon  are  cut  through  the  unaltered  strata,  supposed 
to  be  of  Cretaceous  age,  and  consisting  of  shales  and  sandstones,  of 
which  the  lower  two  miles  dip  to  the  south,  and  the  portion  above  and 
next  to  the  metamorphic  in  the  opposite  direction.  The  interstratitied 
sandstones  have  a  strike  of  FT.  74°  W.,  and  the  shales  between  them 
have  about  the  same  position,  except  that  they  are  more  subject  to 
local  disturbances.  The  shales  contain  beds  of  argillaceous  limestone 
similar  to.  those  observed  in  the  Cretaceous  near  Monte  Diablo,  but 
rather  more  silicious ;  they  also  contain  many  flakes  of  selenite,  and 
occasionallv  considerable  carbonaceous  matter,  which  has  odven  rise  to 
some  prospecting  for  coal.  In  several  places  masses  of  sandstone  were 
found  in  the  shales,  in  the  same  position  with  reference  to  the  sur¬ 
rounding  rocks  as  would  be  occupied  by  dykes.  These  dyke-like 
masses  seem  to  have  originated  in  the  filling  of  fissures  by  sand,  which 
has  since  become  indurated.  They  run  parallel  with  the  strike  of  the 
strata  and  nearly  perpendicular  to  their  dip.  .From  their  superior 
hardness,  which  enables  them  to  resist  weathering  better  than  the 

shales,  they  sometimes  stand  out  from  the  surface  in  long  lines  like 

% 

walls.  The  tendency  of  the  rock  of  which  these  pseudo-dykes  are 
formed  to  weather  in  nodules,  or  with  a  concentric  structure,  adds  to 
the  resemblance  to  artificial  masonry. 

At  about  four  miles  from  the  mouth  of  the  canon  the  metamorphic 
begins  cpiite  abruptly,  the  entire  change  taking  place  within  a  distance 
of  a  few  hundred  feet,  and  within  this  range  rocks  may  be  found  in 
every  stage  of  alteration.  In  this  vicinity  and  position,  a  little  serpen¬ 
tine  occurs, but  it  was  not  seen  farther  up  the  canon,  and  no  boulders 
of  it  were  observed  in  the  stream.  Its  dark  color  has  led  to  its  beiim 

O 

“  prospected”  for  coal,  and  the  same  is  the  case  with  regard  to  the  dark 
jaspers  a  little  farther  up  the  canon. 

The  several  ridges  that  lie  between  the  nearly  parallel  branches  of 
Lone  Tree  Creek,  above  this  point,  run  almost  parallel  with  the  strike 


MOUNT  HAMILTON  GROUP. 


41 


of  the  altered  strata.  Jaspers  abound  in  them  and  mica-slate  occurs  in 
boulders  in  the  canon.  Lying1  south  of  the  canon,  and  about  four  miles 
hack  from  the  plain  of  the  San  Joaquin,  is  a  series  of  high  sandstone 
ridges,  having  a  strike  of  X.  70°  to  75°  W.,  and  dipping  to  the  north¬ 
east,  sometimes  nearly  vertically.  These  same  strata  on  the  southeast 
form  the  high  ridges  lying  between  Mount  Oso  and  the  plain,  and  rising 
to  the  height  of  2000  to  2100  feet. 

The  outer  edge  of  the  hills,  extending  from  two  to  three  miles  above 
the  mouth  of  Lone  Tree  Canon  to  Hospital  Canon,  forms  a  table-land 
about  two  hundred  feet  above  the  plain,  and  from  one  to  two  miles 
wide.  This  appears  to  be  the  remains  of  an  ancient  terrace,  rising  as 
we  go  back  towards  the  hills,  and  cut  into  many  irregular  arroyos,  or 
gullies;  it  is  underlaid  by  soft  Cretaceous  shales,  and  covered  with  a 
deposit  of  gravel,  in  some  places  from  one  hundred  to  two  hundred  feet 
in  thickness,  having  a  gentle  dip  away  from  the  mountains,  and  com¬ 
posed  chiefly  of  pebbles  of  the  metamorphic  rocks  above.  When  seen 
from  the  valley,  at  a  distance  of  a  few  miles,  this  terrace  seems  to  be 
a  regular,  even  plain ;  but,  on  examination,  it  is  found  to  he  eroded 
into  innumerable  rounded  hills  and  ridges:  it  is  about  six  hundred  feet 
above  the  sea-level. 

Hospital  Canon  is  parallel  with  Lone  Tree  Canon ;  it  is  about  two 
or  three  miles  southeast  of  it,  and  resembles  it  in  its  geological  charac¬ 
ters.  The  strata  are,  however,  better  exposed,  and  everywhere  dip  to 
the  northeast  at  an  angle  of  from  40°  to  60°  ;  the  strike  curves  around 
gently  towards  the  meridian  as  we  approach  the  plain.  These  rocks 
are  all  Cretaceous,  consisting  of  sandstones  and  shales;  the  sandstone 
bands  are  less  contorted  than  the  shales,  as  was  observed  in  Lone  Tree 
Canon. 

The  summit  of  Mount  Oso,  which  lies  between  the  Hospital  Canon 
and  Arroyo  del  Puerto,  is  3383  feet  above  the  sea-level ;  it  is  com¬ 
posed  of  jaspers,  generally  dull-red,  but  often  gray  and  green,  with 
reticulations  of  quartz  like  the  rocks  of  Monte  Diablo.  On  the 
north  slope,  the  shales,  as  well  as  the  interstratified  sandstones,  were 
less  altered,  yet  all  partly  metamorphosed.  About  two  miles  north  of 
the  summit  the  stratification  can  be  easily  traced,  the  beds  dipping 
north  and  having  a  nearly  east  and  west  trend,  but  curving  as  we  pass 


GEOL.  VOL.  I. — 0 


42 


GEOLOGY  OF  THE  COAST  RANGES. 


to  the  east.  Here,  as  elsewhere  in  this  region,  the  beginning  of  the 
metamorpliism  is  distinctly  marked  by  the  presence  of  forest  trees, 
scattered  over  the  surface  much  more  abundantly  than  on  the  unal¬ 
tered  rocks;  some  species,  as  Quercus  Garry  ana,  occurring  only  on  the 
metamorphic.  On  the  northeast  of  Mount  Oso,  a  depression  extends 
along  in  a  line  very  nearly  marking  the  edge  of  the  metamorphic,  in 
which  are  the  sources  of  the  Arroyo  de  las  Piedras  on  the  south,  and  a 
branch  of  Hospital  Creek  on  the  north.  Between  this  depression  and 
the  plain  are  high  ridges,  the  most  elevated  of  which  is  about  2100  feet 
above  the  sea.  They  are  all  made  up  of  unaltered  sandstones,  having 
a  strike  of  N.  60°  to  65°  W.,  and  dipping  at  quite  a  high  angle  to  the 
northeast.  These  strata  everywhere  curve  more  to  the  south  as  they 
are  traced  eastward  towards  the  plain. 

The  Arroyo  del  Puerto  is  the  next  considerable  canon  south  of  Hos¬ 
pital  Creek,  and  is  distant  about  two  miles  from  it.  Like  the  others 
in  this  vicinity,  it  breaks  through  the  strata  at  nearly  right  angles  to 
their  strike,  and  it  extends  back  into  the  high  metamorphic  region  in 
the  centre  of  the  chain,  to  a  distance  of  about  sixteen  miles  from  the 
plain  in  a  direct  line.  The  strike  of  the  strata  bends  to  the  south  some 
15°  or  more  where  the  canon  breaks  through.  The  belt  of  unaltered 
strata  between  the  metamorphic  and  the  plain  is  about  six  miles  wide, 
and  consists  of  steep,  dry  ridges,  nearly  destitute  of  trees.  The  ravines 
are  dry  ;  or,  if  water  is  found  in  them  in  the  summer,  it  is  alkaline,  and 
the  alkaline  salts  effloresce  on  the  exposed  surfaces  of  the  sandstones. 
The  water  from  the  metamorphic  is  less  contaminated,  but  not  wholly 
free  from  alkali.  The  hills  rise  to  an  elevation  of  from  2000  to  2400 
feet,  and  there  are  many  points  above  2000  feet;  these  high  ridges  are 
generally  made  up  of  sandstone,  the  depressions  between  them  being 
hollowed  in  the  softer  shales.  These  rocks  closely  resemble  the  Cre¬ 
taceous  shales  and  sandstones  seen  near  Monte  Diablo,  and  the  shales 
contain  similar  beds  of  hydraulic  limestone,  but  of  a  more  silicious 
variety  than  that  noticed  farther  north.  From  the  peculiar  wearing 
away  of  these  strata,  the  sandstones  have  a  less  dip  on  the  summits 
of  the  ridges  than  they  have  in  the  canons;  thus  giving  a  curved  ap¬ 
pearance  to  the  stratification,  as  seen  in  section.  A  few  Cretaceous 
fossils  were  found  here,  both  in  place  and  in  boulders;  but,  on  the 


MOUNT  HAMILTON  GROUT. 


43 


whole,  these  strata  are  remarkably  destitute  of  organic  remains.  All 
the  rocks  exposed  in  this  canon  are  of  Cretaceous  age,  as  was  shown 
both  by  lithological  characters  and  by  the  fossils,  unless  it  be  the  ex¬ 
treme  outer  band  of  strata  next  the  plain ;  this  consists  chiefly  of  a 
conglomerate,  which  rises  about  1000  feet  above  the  plain  and  1300 
feet  above  the  sea,  forming  a  marginal  ridge,  behind  which  is  a  series 
of  canons,  on  both  sides  of  Puerto  Creek,  excavated  in  the  soft  shales. 
The  conglomerate  which  forms  the  crest  of  the  ridge  is  of  a  coarse 
variety,  containing  many  kinds  of  pebbles,  mostly  of  metamorphic 
rock  different  in  character  from  that  of  the  Monte  Diablo  chain.  The 
strike  is  £7.  45°  W.,  north  of  the  Puerto,  and  N.  30°  W.  south  of  it; 
the  dip  is  to  the  northeast,  40°  to  45°.  The  stream  breaks  through  this 
ridge  by  a  narrow  gorge  or  gate,  which  gives  the  name  to  the  canon. 

The  most  noticeable  feature  of  these  strata  is,  as  Professor  Brewer 
remarks,  their  enormous  thickness.  The  horizontal  distance  across  the 
section,  at  right-angles  to  the  strike,  is  six  miles.  The  dip  is  invariably 
to  the  northeast,  often  as  high  as  70°,  and  never,  so  far  as  seen,  below 
40°,  and  this  only  near  the  margin  of  the  plain.  At  50°  dip,  this 
would  represent  a  thickness  of  23,700  feet,  while  the  average  dip 
seemed  higher.  The  whole  of  this  section  was  passed  over  twice,  and 
the  outer  half  four  times,  yet  no  indication  of  folds  were  observed.  If 
this  be  so,  it  is  indeed  extraordinary;  but  other  facts  collected  in  this 
region  justify  us  in  the  belief  that  the  strata  are  indeed  developed  to 
an  almost  incredible  thickness. 

On  ascending  the  canon  the  metamorphic  is  first  met  with  at  about 
six  miles  from  the  margin  of  the  plain.  Here  the  sandstones  become 
more  nearly  vertical,  and  the  metamorphism  begins  suddenly.  The 
principal  varieties  are  metamorphic  sandstones,  jaspery  slates,  and  ser¬ 
pentine  ;  the  latter  the  least  abundant.  Patches  of  rock  which  have 
entirely  escaped  the  metamorphic  action  lie  enclosed  in  the  altered 
strata,  and  exhibit  the  usual  characters  of  the  Cretaceous  shales  and 
sandstones.  The  metamorphic  mass  is  exceedingly  broken,  forming  a 
series  of  ridges  nearly  thirty  miles  across,  many  points  rising  to  above 
3500  feet,  and  some  to  over  4000.  Of  these  Mount  Hamilton  is  the 
culmination,  being  4443  above  high  tide.  These  hills  have  a  very 
complicated  topography,  and  tire  region  is  one  which  has  been  but 


44  GEOLOGY  OF  THE  COAST  RANGES. 

little  explored;  in  fact,  few  portions  of  tlie  State  are  less  frequently 
trodden  by  the- foot  of  either  hunter  or  explorer.  It  is  rendered  for¬ 
bidding  by  its  dryness  as  well  as  its  roughness,  and  the  thick  growth 
of  cliamisal  over  portions  of  it,  which  renders  it  extremely  unpleasant 
to  traverse;  as  there  is  no  reason  to  believe  that  it  will  ever  he  valuable 
for  its  mineral  productions,  it  will  probably  remain  for  an  indefinite 
period  what  it  now  is, — a  barren  wilderness. 

Orestimba  Canon  is  the  next  considerable  opening  in  the  range  to¬ 
wards  the  southeast,  and  it  is  eleven  miles  distant  from  the  Puerto; 
like  the  other  canons  mentioned,  it  gives  passage  to  a  stream  heading 
in  the  metamorphic  mass  of  mountain  above,  and  flowing  down  and 
breaking  through  the  unaltered  strata  nearly  at  right  angles  to  their 
strike. 

In  passing  along  the  plain,  as  well  as  from  the  elevations  back,  it  is 
seen  that  the  high  marginal  ridge,  mentioned  as  occurring  at  Arroyo 
del  Puerto,  sinks  into  the  plain  to  the  southeast  of  that  canon,  long 
before  reaching  Orestimba.  At  the  last-named  canon  a  number  of  suc¬ 
cessive  ridges  lie  back  of  each  other,  the  highest  rising  to  2360  feet, 
and  many  to  over  2200  feet,  all  made  up  of  unaltered  strata,  having  a 
northeast  dip.  The  outer  portion  of  these  was  referred  to  the  Tertiary 
and  the  remainder  to  the  Cretaceous,  on  the  evidence  of  fossils  found. 

At  the  mouth  of  the  canon  the  Tertiary  extends  back  about  three 
miles,  having  a  dip  of  about  45°,  where  it  lies  upon  the  Cretaceous 
and  perfectly  conformable  with  it,  the  inclination  diminishing  towards 
the  plain  and  becoming  very  low  at  the  outer  margin  of  the  hills.  This 
margin  is  not  sharply  defined  where  the  Tertiary  forms  the  edge ;  in 
such  cases  the  ridges  become  low  and  rounded  and  gradually  die  out, 
being  covered  more  or  less  extensively  with  very  modern  deposits  as 
they  disappear.  This  condition  of  things  contrasts  in  a  decided  man¬ 
ner  with  the  abrupt  termination  of  the  Cretaceous,  when  it  meets  the 
plain  without  any  intervening  Tertiary. 

Between  the  Tertiary  and  the  metamorphic  lies  a  belt  of  unaltered 
Cretaceous,  about  four  miles  wide  in  its  narrowest  place,  the  strike  of 
the  strata  averaging  about  K  30°  W.  to  K  33°  W.,  but  often  curving 
round  to  a£  much  as  X.  45°  W.  A  change  of  about  15°  in  the  direc¬ 
tion  of  the  strata  occurs  at  the  entrance  of  the  canon,  where  they  bend 


MOUNT  HAMILTON  GROUP. 


45 


more  to  the  south  and  run  out  into  the  plain  with  a  direction  of  N.  15° 
W.  At  the  outer  edge  of  the  Cretaceous  it  lias  a  dip  of  45°;  but,  for 
at  least  three  miles,  it  is  from  50°  to  60°,  averaging  at  least  55°,  indi¬ 
cating,  as  at  the  Arroyo  del  Puerto,  an  enormous  thickness  of  the 
strata  of  this  age.  The  predominating  rocks  are  sandstones,  but  shales 
are  frequently  interstratificd  with  them.  No  evidence  of  any  folds  in 
these  beds  could  be  obtained  here.  The  hills  formed  by  the  Tertiary 
are  very  unlike  those  made  up  of  Cretaceous  rocks;  they  are  less  regu¬ 
lar,  more  rounded  in  their  outlines,  and  they  sink  very  gradually  into 
the  plain;  they  are  also  quite  destitute  of  trees,  while  the  Cretaceous 
hills  have  scattered  oaks  upon  them  (Q.  Garryana ),  chiefly  on  their 
northern  slopes. 

Pacheco’s  Pass  is  the  most  considerable  depression  in  the  chain  to 
the  southeast  of  Livermore’s  Pass.  A  wide  valley  extends  back  from 
the  San  Joaquin  Plain,  entirely  across  the  unaltered  strata  and  some 
distance  into  the  metamorphic,  forming  a  basin  of  several  square  miles 
in  extent,  with  a  rim  of  hills  of  unaltered  rocks  in  front.  This  valley 
or  basin  is  known  as  the  San  Luis  Gonzaga  Ranch. 

North  of  the  mouth  of  San  Luis  Creek  several  steep  ridges  form 
the  rim,  the  strata  consisting  of  conglomerates,  sandstones,  and  shales, 
apparently  all  Cretaceous,  with  a  strike  of  N.  30°  to  34°  W.  and  a  dip 
to  the  northeast,  but  the  latter  very  variable,  from  40°  to  80°,  or  even 
sometimes  vertical.  The  conglomerates  generally  form  the  crests  of 
the  ridges  and  are  very  coarse,  containing  numerous  boulders  as 
lars;e  as  one  or  two  cubic  feet  in  size,  and  Great  numbers  of  them 
are  over  six  inches  in  diameter.  These  consist  of  porphyry,  granite, 
and  various  forms  of  metamorphic  rock,  entirely  unlike,  however, 
to  the  metamorphic  Cretaceous  of  the  centre  of  the  chain.  These 
boulders  weather  out  from  the  rock  in  immense  numbers,  often  en¬ 
tirely  covering  the  ground;  they  are  all  much  worn  and  thoroughly 
rounded  and  polished. 

The  strata  on  the  north  of  the  valley  have  a  strike  of  N.  30°  W. ;  on 
the  south,  N.  37°  W.,  with  a  dip  to  the  northeast  of  42°,  diminishing 
towards  the  plain. 

The  following  species  of  Cretaceous  fossils  were  obtained  on  the  San 
Luis  Gonzaga  Ranch  : 


40 


GEOLOGY  OF  THE  COAST  RANGES. 


Ammonites  Chicoensis 
Baculites  Chicoensis, 
Lunatia  Hornii, 

L.  NUCIFORMIS, 

L.  Conrad  i  an  a, 
Cylichna  costata, 
Mactra  Ashburnerii, 


Avicula  pellucida, 
Trigonia  Evansii, 
Arca  gravida, 

CuCULLAiA  TRUNCATA, 
NuCULA  TRUNCATA, 
Lkda  PROTEXTA, 

Lima  appressa. 


In  following  this  belt  of  unaltered  Cretaceous  rocks  southeast  along 
the  margin  of  the  chain  from  Corral  Hollow  to  this  point,  it  appears 
evident  that  the  mass  of  strata  increases  in  thickness,  while  the  shales 
gradually  diminish,  the  sandstones  predominating  more  and  more ;  the 
iuterstratihed  limestones  in  the  shales  also  disappear  to  a  considerable 
extent,  and  become  more  silicious  in  character  than  they  were  observed 
to  he  near  Monte  Diablo.  There  is  also  a  great  increase  in  the  deve¬ 
lopment  of  the  conglomerates,  both  in  the  frequency  and  the  thickness 
of  the  beds,  and  in  the  size  of  the  pebbles  of  which  they  are  made  up, 
as  we  2:0  towards  the  north.  The  unaltered  beds  of  Cretaceous  and 
Tertiary  extend  along  the  eastern  edge  of  the  Monte  Diablo  Range  to 
the  north  as  far  as  where  it  joins  the  Sierra  Nevada,  although  the 
region  south  of  Pacheco’s  Pass  has  only  been  very  cursorily  examined 
by  our  parties. 

The  metamorpliic  region  in  the  vicinity  of  the  pass  is  marked  by  a 
depression  across  the  whole  chain,  the  ridges  rising  to  about  1600  feet 
in  the  vicinity  of  the  summit,  which  itself  is  1472  feet  above  the  sea- 
level.  These  hills  rapidly  rise  in  elevation  as  they  extend  towards  the 
south,  while  to  the  north  their  increase  of  altitude  is  more  gradual. 
Near  Butterfly  Peak,  about  eight  miles  from  the  plain  and  four  miles 
north  of  the  pass,  there  is  an  abundance  of  jasper  and  other  evidently 
metamorphic  Cretaceous  rocks,  which  are  much  disturbed  in  position, 
but  have  a  general  strike  of  about  N.  45°  to  55°  W.,  and  a  north¬ 
easterly  dip.  Across  the  centre  of  the  chain,  along  the  line  of  the  pass, 
the  rock  appears  to  be  all  metamorphic  Cretaceous,  which  in  places  is 
not  highly  altered,  but  still  in  the  whole  so  much  so  that  no  satisfactory 
section  can  be  given.  In  circumscribed  localities  the  stratification  can 
be  clearly  made  out,  but  in  general  the  beds  are  broken,  twisted,  and 
contorted,  as  if  acted  on  by  pressure  from  several  different  directions. 


MOUNT  HAMILTON  GROUP. 


47 


To  the  south  of  the  pass  there  are  several  high  peaks,  one  of  which, 
without  a  name,  was  ascended  and  found  to  he  3412  feet  above  the  sea; 
this  one  is  two  miles  northwest  by  north  from  Mariposa  Peak.  A 
little  south  of  west  from  this  is  another  high  point,  about  3550  feet  in 
elevation,  and  the  Mariposa  Peak,  or  what  was  supposed  to  he  that,  is 
about  3800  feet  high.  Pacheco’s  Peak,  2845  feet  high,  and  three  miles 
southeast  of  Hollenbeck’s  house,  in  the  pass,  is  a  conspicuous  landmark 
from  the  San  Jose  Valley,  as  it  rises  about  five  hundred  feet  above  the 
surrounding  ridges  and  terminates  in  a  very  sharp  point.  These  high 
points  form  a  belt  of  trachyte  running  across  the  chain  in  a  direction  of 
about  17.  55°  W.  It  is  supposed  to  run  through  to  the  Panoche  Plain, 
but  was  not  explored  farther  than  the  peak  noticed  above  as  3412  feet 
high.  As  far  as  could  be  made  out,  this  eruptive  volcanic  mass  has 
had  no  influence  on  the  upheaval  or  metamorphism  of  the  surrounding 
strata;  it  seems  to  have  been  poured  out  after  the  surface  had  assumed 
nearly  its  present  condition ;  it  cannot  hv  any  means  be  considered  as 
forming  an  axis  of  upheaval. 

The  region  lying  oft*  to  the  northwest  of  Hollenbeck’s  for  six  or  eight 
miles,  as  far  as  a  point  visited  and  found  to  be  2362  feet  in  elevation, 
is  all  of  metamorphic  rock.  Near  the  point  measured,  fine  specimens 
of  actinolite  were  found  and  mica-slate  occurs.  No  satisfactory  section 
was  obtained  in  this  region,  as  the  rocks  are  too  much  disturbed  and 
metamorphosed  to  allow  of  their  dip  and  strike  being  determined. 
Contorted  jaspers  were  observed  near  Hollenbeck’s. 

A  characteristic  outcrop  of  the  metamorphic  rock  in  this  vicinity  is 
figured  in  the  annexed  wood-cut  (Fig.  5).  It  is  called  Hollenbeck’s 
Pock,  and  it  rises  to  about  eight  hundred  feet  above  the  pass  at  that 
point. 

Having  thus  given  a  sketch  of  the  geology  of  the  eastern  edge  and 
the  adjacent  interior  region  of  the  Mount  Hamilton  group,  and  having 
made  our  way  across  it  through  Pacheco’s  Pass  into  the  San  Jose 
Valley,  we  may  now  follow  up  its  western  side,  giving  such  observa¬ 
tions  as  were  made  by  the  corps  in  passing  up  the  valley,  and  making 
occasional  excursions  into  the  heart  of  the  region  from  its  western 
edge. 

The  most  noticeable  feature  of  this  side  of  the  range  is  that  there  is 


48 


GEOLOGY  OF  THE  COAST  RANGES. 


an  outer  or  marginal  range  of  lulls  all  along  tlie  interior  mass  of  moan- 
tains,  the  valleys  of  Coyote  Creek,  the  Penitencia  (Canada  de  Pala),  and 


Fig.  5. 


HOLLENBECK’S  ROCK — PACHECO’S  PASS. 


of  Calaveras  Creek,  marking  this  division.  The  course  of  the  Coyote 
and  of  the  Penitencia  Creeks  offers  a  good  illustration  of  the  peculiar 
geography  of  the  Coast  Ranges.  They  head  together  in  or  near  a  sort 
of  lagoon  in  the  centre  of  the  Canada  de  Pala.  The  Penitencia  flows 
northwest  a  few  miles  in  a  narrow  valley  between  high  ridges,  and 
then  turns  suddenly,  breaks  through  the  western  one,  and  emerges 
into  the  San  Jose  Plain  ;  the  Coyote  flows  northeast  from  its  source 
for  about,  eight  miles ;  it  then  breaks  through  a  high  ridge  and  enters 
the  Las  Animas  Valley,  resuming  its  former  southeast  course  and 
keeping  it  for  about  six  miles,  when  it  again  cuts  through  a  ridge  to 
the  west,  and  after  issuing  from  it  turns  and  runs  parallel  with  its 
former  course  but  in  the  opposite  direction,  and  finally  unites  with  the 
Penitencia  near  the  lower  end  of  the  San  Jos£  Valley.  The  ridge  just 
mentioned  as  the  one  the  Coyote  breaks  through  to  issue  on  to  the  San 


MOUNT  HAMILTON  GROUP. 


49 


Jose  Plain  is  continuous  for  many  miles,  with  the  exception  of  this 
break.  It  rises  about  a  thousand  feet  above  the  plain,  and,  when  seen 
from  the  hills  on  the  opposite  side  of  the  valley,  appears  like  a  terrace, 
having  a  darker  brown  color  than  the  hills  beyond.  It  is  composed 
entirely  of  metamorphic  rocks ;  the  most  of  it  a  sort  of  diorite,  very 
hard  and  crystalline.  Some  of  it  is  decidedly  amygdaloidal,  having  its 
cavities  filled  with  carbonate  of  lime.  This  rock  was  considered  by  Mr. 
Brewer  as  probably  of  metamorphic  origin,  although  it  had  in  places 
cpiite  the  appearance  of  an  eruptive  mass.  The  deep  brown  color  of 
this  range,  as  noticed  when  seen  from  a  distance,  is  due  to  the  multi¬ 
tude  of  boulders  or  loose  pieces  of  the  dark-colored  rock  scattered  over 
the  surface. 

The  ridge  back  or  next  east  of  the  one  just  noticed  is  made  up  of 
sandstone  mostly  unaltered,  but  occasionally  a  little  metamorphosed, 
and  having  a  strike  parallel  with  the  direction  of  the  ridge,  about  R. 
30°  to  34°  W.,  but  sometimes  as  much  as  H.  45°  W. ;  its  dip  is  to  the 
northeast,  but  not  high,  generally  less  than  25°.  Some  serpentine  was 
seen  at  the  base  of  the  ridge.  These  hills  supported  a  much  heavier 
growth  of  wild  oats  than  the  metamorphic  ridge  to  the  west. 

This  marginal  ridge  was  again  visited  at  a  point  due  north  of  our 
camp  (Xo.  47),  at  the  Ojo  de  Agua  de  la  Coche,  and  about  five  miles 
northwest  of  the  place  where  the  Coyote  Creek  breaks  through  it. 
As  when  examined  farther  south,  so  here  it  was  found  to  be  made  up 
of  metamorphic  rock,  with  some  masses  possibly  of  eruptive  origin. 
Serpentine  occurs  also,  but  chiefly  at  the  base  of  the  ridge.  In  con¬ 
nection  with  these  serpentine  rocks  near  the  summit,  there  is  a  large 
deposit  of  carbonate  of  magnesia,  which  occurs  scattered  through  the 
rocks  in  masses  of  considerable  size,  irregular  in  their  form  and  not 
connected  into  a  vein.  The  thickest  of  these  were  from  two  to  three 
feet  through ;  and  their  surface  often  weathers  in  large  botryoidal 
masses,  showing  a  distinct  concentric  structure  pervading  the  mate¬ 
rial.  This  variety  of  the  carbonate  of  magnesia  is  a  peculiar  one,  as 
it  is  extremely  hard  and  compact,  breaking  with  difficulty  and  with  a 
conchoidal  fracture,  and  ringing  under  the  hammer  like  a  piece  of 
metal ;  it  is  white  and  exceedingly  pure.  This  same  material  occurs 
in  other  places  in  the  Monte  Diablo  Range;  it  is  often  supposed  to 

GEOL.  VOL.  T. — 7 


50 


GEOLOGY  OF  THE  COAST  RANGES. 


be  of  value  for  the  manufacture  of  porcelain,  and  is  called  porcelain 
earth,  with  which,  however,  it  has  no  affinity,  nor  is  it  of  any  value  at 
present. 

Spurs  of  this  metamorphic  range  of  foot  hills  extend  out  into  the 
San  Jos6  Valley,  and  appear  to  nearly  cross  it,  as  low  rounded  hills 
with  a  dark  brown  soil  stretch  along  in  a  line  a  few  miles  south  of 
San  Josd,  partially  closing  up  the  valley,  which  expands  into  a  plain 
both  to  the  north  and  the  south  of  them.  At  all  events,  this  meta¬ 
morphic  ridge  does  not  follow  the  western  edge  of  the  Monte  Diablo 
Range  continuously,  for  on  exploring  the  hills  bordering  the  valley 
directly  east  of  San  Josd  they  were  found  to  consist  of  sandstones 
unaltered,  or  only  slightly  metamorphosed  in  places.  These  sand¬ 
stones  have  a  strike  nearly  parallel  with  the  chain  and  a  high  dip 
to  the  northeast,  sometimes  standing  nearly  vertical.  They  contain 
numerous  fossils,  although  mostly  in  a  bad  state  of  preservation ; 
enough  were  collected,  however,  and  determined,  to  fix  the  age  of 
this  ridge  as  Tertiary.  Its  elevation  is  from  1000  to  1200  feet  above 
the  valley  at  its  base,  and  its  culminating  point,  Master’s  Hill,  is  1604 
feet  above  the  sea, 

Passing  east,  after  crossing  this  ridge  and  the  valley  at  its  eastern 
base,  called  “  Canada  de  Pala,”  we  come  to  a  region  of  highly  meta¬ 
morphic  rock,  which  in  some  places  might  almost  be  called  mica-slate. 
On  its  eastern  side  is  a  deep  valley,  in  which  Calaveras  Creek  heads, 
and  crossing  this  we  strike  the  ridge  which  leads  to  the  summit  of 
Mount  Hamilton,  in  a  direction  nearly  transverse  to  the  main  chain, 
or  northeast  and  southwest.  This  ridge  is  of  metamorphic  sandstone, 
although  not  so  highly  altered  as  are  portions  of  the  great  mountain 
mass  to  the  east.  The  strata  are  much  broken,  often  standing  nearly 
vertical,  and  having  a  strike  from  northeast  to  southwest,  indicating 
great  disturbances  in  this  region.  Mount  Hamilton,  the  highest  point 
of  the  group,  and  the  highest  peak  north  of  San  Carlos,  as  far  as  Clear 
Lake,  is  4448  feet  above  the  level  of  the  sea.  From  its  summit,  which 
is  very  easy  of  access,  there  is  a  fine  view,  not  only  of  the  beautiful  and 
fertile  valley  of  San  Jos6,  but  of  the  wild  and  entirely  uninhabited  and 
unknown  region  to  the  east,  northeast,  and  southeast.  To  any  one  de¬ 
sirous  of  forming  an  idea  of  the  character  of  the  mountains  in  this  part 


/ 


MOUNT  HAMILTON  GROUP. 


51 


of  the  Coast  Ranges,  a  trip  from  San  Jos6  to  Mount  Hamilton  may  be 
recommended.  It  can  be  made  in  a  day,  although  a  long  one  is  re¬ 
quired,  as  the  distance  from  San  Jose  to  the  summit  of  the  mountain 
is  about  thirteen  miles  in  a  straight  line,  and  there  are  two  high  ridges 
to  be  crossed  before  arriving  at  the  base  of  the  mountain  itself.  The 
valley  of  the  Calaveras,  called  here  the  “Arroyo  Hondo,”  offers  a  plea¬ 
sant  camping  ground  to  those  who  wish  to  devote  more  than  one  day 
to  the  excursion.  No  other  peak  in  the  Coast  Ranges,  of  anything 
like  the  same  elevation,  offers  so  easy  an  ascent. 

The  western  edge  of  this  portion  of  the  chain  was  again  examined 
at  the  Arroyo  de  la  Penitencia,  or  “  Arroyo  Aguage,”  as  it  is  also 
called,  which  is  about  six  miles  northwest  of  the  place  where  this  ridge 
was  crossed  in  going  to  Mount  Hamilton.  At  the  entrance  of  the 
canon  there  is  a  slight  development  of  conglomerate,  made  up  chiefly 
of  pebbles  of  the  metamorphic  rock,  and  having  a  dip  to  the  south- 
west.  Above  this,  for  three  or  four  miles,  nothing  was  seen  hut  meta¬ 
morphic  sandstones  and  slates.  The  so-called  “  Alum  Rock”  is  a  soft, 
slightly  metamorphosed  sandstone,  on  the  surface  of  which  various 
sulphates,  derived  from  the  decomposition  of  iron  pyrites  and  a  little 
copper  pyrites,  effloresce.  Near  the  “  Upper  Alum  Rock”  there  are 
sulphur  springs,  containing  carbonate  of  soda  and  some  sulphuretted 
hydrogen.  They  are  somewhat  warm,  hut  the  volume  of  water  is  not 
large.  Near  these  springs  there  is  a  metamorphic  slate  which  is  jet 
black,  and  hence  has  been  mistaken  for  coal ;  it  has  a  dip  to  the  south¬ 
west,  and  a  strike  of  about  N.  60°  W.,  but  both  strike  and  dip  are 
variable.  Some  copper,  in  the  native  state,  has  been  found  here.  The 
specimens  which  we  saw  were  in  the  form  of  small  grains,  in  a  hard 
silicious  rock;  the  quantity  is  too  small  to  be  worth  working,  although 
some  “prospecting”  has  been  done  here  and  a  copper  excitement 
started. 

The  most  interesting  feature  of  this  ridge  is  the  manner  in  which  it 
has  undergone  local  metamorphism.  Although  quite  metamorphosed, 
as  has  been  stated,  in  the  Arroyo  Aguage,  yet  to  the  north  and  the 
south,  at  a  short  distance,  the  same  strata  are  in  their  original  condition, 
soft  and  fossil iferous.  Although  not  as  thoroughly  metamorphosed  as 
some  or  most  of  the  altered  Cretaceous,  yet  these  Tertiary  strata  show 


52 


GEOLOGY  OF  THE  COAST  RANGES. 


that  the  same  kind  of  action  has  taken  place  in  rocks  of  this  very  re¬ 
cent  epoch,  which  we  have  already  so  often  had  occasion  to  notice  as 
having  effected  such  extensive  changes  in  the  condition  of  the  older 
underlying  strata. 

The  next  point  where  this  range  of  hills  was  examined  was  back  of 
the  Milpitas  Ranch,  nearly  north  of  San  Jose  and  east  of  Alviso. 
There  is  a  high  mass  of  hills  here,  between  the  head-waters  of  the 
Coyote  and  Calaveras  Creeks,  exceedingly  broken,  and  divided  into 
subordinate  ridges,  with  many  knobs  more  or  less  connected,  rising 
from  two  hundred  to  four  hundred  feet  above  the  general  level  of 
the  mass,  and  so  nearly  of  a  height  that  it  would  be  difficult  to  make 
out  which  is  the  most  elevated.  These  hills  are  made  up  of  strata  of 
sandstone,  standing  vertically  or  having  a  high  dip  to  the  northeast, 
rarely  in  the  opposite  direction.  The  strike  is  very  much  broken,  as 
can  easily  be  recognized  at  a  distance  by  inspecting  the  long  lines  of 
outcropping  strata;  it  varies  between  H.  55°  W.  and  H.  35°  E.,  but  is 
usually  from  H.  15°  W.  to  H.  45°  W.  Tertiary  fossils  were  obtained 
in  considerable  quantity  in  this  range  of  hills,  but  usually  in  a  very 
poor  state  for  determination,  owing  to  the  hardness  of  the  rock  in 
which  they  were  imbedded. 

This  Tertiary  ridge  extends  along  to  the  northwest,  between  the  San 
Jose  and  Calaveras  Valleys.  Back  of  San  Jose  Mission  rise  hills  of 
unaltered  sandstone  with  very  abrupt  sides,  in  which  the  strata  dip  to 
the  northeast.  In  the  hills  near  the  “  Seventeen  Mile  House,”  one 
mile  northeast  of  the  mission,  the  strata  are  fossiliferous,  the  species 
being  the  same  Tertiary  ones  found  along  the  ridge  at  various  points 
to  the  southwest.  Back  of  this  range  of  hills  the  Calaveras  Creek 
Hows  to  the  northwest,  and  after  uniting  with  Alameda  Creek  they 
break  through  the  ridge  by  a  very  deep  and  abrupt  canon. 

% 

Section  V. — Monte  Diablo  Range,  south  of  Pacheco’s  Pass. 

Of  the  geological  structure  of  the  chain  to  the  south  of  Pacheco’s 
Pass,  only  some  general  ideas  can  be  given,  as  our  investigations  in 
that  region  were  of  necessity  quite  limited.  We  passed  through  the 
chain  diagonally  in  a  southeast  direction  from  San  Juan  to  the  Hew 


MONTE  DIABLO  RANGE. 


53 


<? 


Idria  mines,  tlie  road  giving  us  an  opportunity  to  observe  the  geology 
at  various  points  for  a  distance  of  about  sixty  miles. 

We  tirst  followed  up  from  Sail  Juan  the  San  Benito  River,  a  branch 
of  the  Pajaro.  The  hills  on  the  north  side  are  of  metamorphic  rock, 
and  presumed  to  be  a  continuation  of  those  described  as  existing 
near  Pacheco’s  Pass.  The  San  Benito  exhibits  tine  terraces  along  its 
course.  At  a  point  about  ten  miles  from  San  Juan  two  of  them  were 
measured ;  one  near  the  stream  and  fifteen  feet  above  it,  and  another 
twenty  rods  farther  back  and  twenty  feet  in  height.  The  valley  of 
the  San  Benito  is  narrow  and  marks  the  division  between  the  Gavilan 
and  the  Monte  Diablo  Ranges;  the  different  ranges,  as  has  been  before 
remarked,  gradually  approaching  and  inosculating  as  we  proceed  south¬ 
ward,  so  that  the  distinction  between  them  becomes  almost  entirely  an 
artificial  one.  This  whole  region  was  extremely  dry  at  the  time  of  our 
visit  (July,  1861),  no  water  being  obtainable  on  the  route  except  at  a 
few  stations,  usually  from  ten  to  fifteen  miles  apart;  and  when  obtained 
it  was  often  so  alkaline  as  to  be  very  disagreeable  to  the  taste. 

From  Tres  Pinos,  thirteen  miles  from  San  Juan,  to  Booker’s  (Camp 
39),  a  distance  of  about  thirteen  miles  in  a  direct  line,  the  road  follows 
the  Arroyo  Joaquin  Soto,  a  branch  of  the  San  Benito,  which  runs 
parallel  with  it  at  a  distance  of  three  or  four  miles.  Soon  after  leaving 
the  Tres  Pinos  we  came  upon  vast  deposits  of  gravel,  or  entirely  uncon¬ 
solidated  detritus,  which  appears  to  be  of  Post-Tertiary  age,  and  which 
forms  a  large  portion  of  the  series  of  ridges  between  the  Gavilan  on  the 
one  side  and  the  Monte  Diablo  Range  on  the  other.  At  the  first  ex¬ 
posure,  about  two  miles  beyond  Tres  Pinos,  the  stratified  detritus  forms 
a  steep  bluff  about  four  hundred  feet  above  the  creek.  The  gravel  is 
made  up  of  pebbles  of  granite,  red  and  green  jaspers,  and  silicious 
slate  and  other  metamorphic  materials ;  the  granite  is  composed  almost 
exclusively  of  red  or  flesh-colored  feldspar  and  quartz,  with  but  little 
mica  or  hornblende.  At  this  point  the  detritus,  or  gravel,  h^|  a  nearly 
horizontal  position.  As  we  pass  up  the  valley,  however,  we  find  it 
very  much  disturbed,  at  some  places  dipping  almost  vertically.  This 
was  especially  observed  at  a  point  where  the  canon  narrows,  a  few  miles 
below  Booker’s.  In  the  vicinity  of  that  place  these  unconsolidated 
deposits  were  examined  in  some  detail  on  both  sides  of  the  road.  The 


54 


GEOLOGY  OF  THE  COAST  RANGES. 


strata  here  are  worn  into  precipitous  canons,  with  hare  bluff  banks  or 
almost  perpendicular  walls,  regularly  stratified,  and  varying  in  fineness 
from  a  coarse  gravel  to  fine  sand,  with  here  and  there  a  thin  band  of 
consolidated  materials,  the  remainder  entirely  in  the  original  condition 
in  which  it  was  deposited,  as  far  as  being  held  together  by  any  cement 
is  concerned.  As  near  as  could  be  made  out,  these  strata  fill  the  valley 
between  the  two  ranges,  dipping  towards  the  centre  from  both  sides, 
forming  a  sort  of  basin  some  six  or  eight  miles  across.  The  thickness 
of  these  deposits  was  enormous ;  one  hill  measured,  south  of  Camp  39, 
was  found  to  be  1274  feet  above  the  valley  at  Booker’s,  or  2330  feet 
above  the  sea;  while  another  hill,  on  the  other  side  of  the  camp,  having 
a  dip  in  the  opposite  direction,  was  estimated  at  1800  feet  above  the 
valley  or  3000  feet  above  the  sea.  Of  both  these  hills  the  entire  mass 
was  evidently  made  up  of  this  unconsolidated  material,  which  so  far 
as  observed  was  entirely  destitute  of  organic  remains.  It  must,  how¬ 
ever,  be  newer  than  the  Miocene,  and  is  probably  of  Post-Pliocene 
age;  yet  it  has  evidently  undergone  great  disturbance  since  its  deposi¬ 
tion,  for  although  we  might  suppose  the  material  to  have  been  washed 
into  a  deep  and  narrow  basin  and  deposited  in  beds  inclined  at  a  con¬ 
siderable  angle,  yet  it  is  impossible  that  it  should  be  supposed  to  have 
had  originally  the  vertical  position  which  it  now  has  in  some  places. 
This  region  gives  one  a  most  vivid  idea  of  how  recently  geological 
changes  of  magnitude  have  taken  place  in  this  part  of  the  State,  and 
furnishes  most  impressive  testimony,  to  add  to  that  obtained  in  other 
places,  in  relation  to  the  lateness  of  the  geological  epoch  during  which 
this  portion  of  the  chain  was  elevated.  Beautiful  exhibitions  of  ter¬ 
races  were  noticed  in  this  canon,  a  few  miles  below  Booker’s.  In 
some  places  as  many  as  five  can  be  seen,  in  others  three  or  four ;  the 
elevation  of  the  highest  above  the  valley  was  estimated  at  about  225 
feet.  It  would  appear  that  the  basin  in  which  these  Tertiary  strata 
were  deposited  was  drained  of  the  water  at  successive  intervals  by  the 
elevation  of  the  basin  itself,  judging  from  the  disturbed  position  of  the 
strata,  it  contains,  and  not  by  the  gradual  wearing  away  of  a  barrier  at 
its  lower  end. 

A  little  above  Booker’s  this  gravel  deposit  is  passed,  and  we  enter 
into  a  region  of  sandstones  and  slates,  which  gradually  assume  a 


MONTE  DIABLO  RANGE. 


55 


thoroughly  metamorphic  character  as  we  approach  Camp  40,  at  the 
sheep-wells,  about  ten  miles  in  a  direct  line  nearly  east  from  Booker’s. 
Here  we  are  near  the  divide,  or  summit  of  the  range,  at  the  head  of 
the  Little  and  Big  Panoehe  Creeks.  The  rocks  here  are  entirely  of  a 
dark  metamorphic,  almost  trappean  material,  the  soil  dry  and  support¬ 
ing  a  thin  crop  of  forage  plants,  with  a  few  scattered  oaks  and  pines. 
The  altitude  of  this  camp  was  about  2200  feet,  the  nights  clear  and 
cold,  the  thermometer  sinking  to  40° ;  the  days,  on  the  other  hand, 
were  extremely  hot,  the  temperature  remaining  at  some  point  between 
90°  and  100°  from  9  a.m.  to  4  p.m.  A  hill  several  miles  north  of 
this  camp  was  visited,  and  its  elevation  found  to  be  about  3750  feet 
above  the  sea.  The  rocks  passed  over  in  going  to  it  were  chiefly  of 
metamorphic  sandstone,  with  a  granular-crystalline  texture ;  mica-slate 
was  also  observed,  forming  a  ridge,  of  which  the  strata  stood  almost 
vertically,  and  had  a  very  variable  strike,  but  usually  somewhere  near 
northwest  and  southeast.  The  texture  of  this  mica-slate  was  very  vari¬ 
able,  at  times  fine  and  again  very  coarse,  with  numerous  small  quartz 
veins  traversing  it,  and  some  imperfect  serpentine  or  other  magnesian 
mineral  disseminated  through  it.  Well-crystallized  actinolite  was  also 
noticed  as  occurring  in  this  rock. 

The  culminating  points  of  the  chain,  in  a  section  across  on  this  line, 
are  probably  from  3850  to  4000  feet,  as  the  view  from  the  point  which 
we  measured,  and  found  to  be  3750  feet  high,  was  a  commanding  one 
on  all  sides,  although  a  few  somewhat  higher  points  were  visible  in 
the  vicinity.  The  summit  of  the  pass,  about  four  miles  southeast  of 
the  sheep-wells,  was  about  2700  feet  in  elevation,  and  here  consider¬ 
able  timber  was  observed,  Quercus  agrifolia  being  the  predominant 
tree.  From  this  divide  we  sank  rapidly  to  the  Panoehe  Plain,  which 
is  a  level  tract,  some  fifteen  miles  in  length  and  six  in  width,  through 
which  runs  the  Big  Panoehe  Creek ;  it  was  -very  dry  and  destitute 
of  vegetation  at  the  time  we  passed  through  it.  It  is  surrounded  on 
all  sides  by  high  ranges  of  hills.  Those  on  the  north  are  of  a  dark- 
colored  rock,  evidently  the  metamorphic  mass  of  the  central  chain 
over  which  we  have  just  passed.  To  the  east  the  hills  were  perfectly 
bare  of  trees,  and  were  distinctly  seen  in  the  distance  to  be  made 
up  of  stratified  rock,  probably  sandstone,  tilted  up  at  a  considerable 


5G 


GEOLOGY  OF  THE  COAST  RANGES. 


angle  and  having  an  exceedingly  arid  appearance.  The  sides  of  the 
Panoclie  Valley  ^re  distinctly  terraced  in  many  places,  the  plain  having 
once  evidently  been  occupied  by  a  lake.  The  range  of  hills  to  the 
east  of  the  Panoclie  Plain  are,  in  all  probability,  of  Tertiary  sand¬ 
stone  ;  while  the  metamorphic  rock  on  the  west  is  presumed  to  be  the 
continuation  of  the  great  belt  of  Cretaceous  wdiich  we  have  traced 
down  from  Monte  Diablo. 

From  our  limited  knowledge  of  the  geography  of  this  region,  no 
portion  of  it  ever  having  been  laid  down  on  a  map  with  any  approach 
to  accuracy,  it  will  be  difficult  to  give  a  clear  idea  of  its  geology.  From 
the  Panoclie  Plain  we  turned  off  at  a  sharp  angle  to  the  south  and  en¬ 
tered  a  narrow  and  abrupt  canon  worn  in  the  unaltered  sandstone  rocks 
which  leads  up  towards  the  New  Idria  mine.  This  canon  is  about  six 
miles  in  length,  and  it  presents  a  picture  of  perfect  aridity,  having  no 
drinkable  water  at  the  time  we  passed  through  it,  and  no  vegetation 
except  a  few  parched  undershrubs.  But  in  some  of  the  side-valleys 
and  over  the  low  hills  in  this  vicinity  sufficient  herbage  grows  to  sup¬ 
port  a  few  cattle,  and  a  ranch  house  is*  found  a  little  above  the  south 
end  of  the  canon,  which  is  called  “  Griswold’s but  what  the  induce¬ 
ments  could  be  to  live  in  such  a  place  it  was  beyond  our  power  to  de¬ 
termine.  In  the  canon  the  sandstone  has  a  general  southerly  dip ;  at 
three  miles  from  the  entrance  it  is  inclined  at  an  angle  of  35°,  and  the 
dip  gradually  increases  in  amount  as  we  go  towards  Griswold’s.  In 
one  place  this  rock  presents  a  very  curious  appearance,  from  the  occur¬ 
rence  in  it  of  numerous  hard  nodules  of  a  few  inches  in  diameter, 
which  project  like  cannon-balls  from  the  weathered  surface.  Some¬ 
times  these  projecting  nodules  are  arranged  in  regular  lines,  which,  in 
connection  with  their  color  and  form,  gives  them  the  appearance  of 
rivet-heads  joining  sections  of  the  rock  together.  Near  the  head  of  the 
canon  there  are  several -bands  of  black  bituminous  shales  in  the  sand¬ 
stone,  dipping  about  55°.  They  are  a  few  inches  in  thickness,  and 
contain  impressions  of  leaves  and  stems  of  plants,  but  these  are  too 
much  impregnated  with  sulphur  for  preservation.  The  locality  has 
been  opened  and  some  rock  excavated,  apparently  under  the  idea  that 
a  valuable  deposit  of  coal  might  exist  there.  There  is,  indeed,  some 
coaly  matter,  but  no  indication  of  enough  to  pay  for  working. 


MONTE  DIABLO  RANGE. 


Quite  a  number  of  well-preserved  Tertiary  fossils  were  found  near 
Griswold’s,  of  which  Mr.  Gabb  notices  the  following : 


Tiuptera  clavata, 

Nassa  interstriata, 
Standella  falcata, 
Hemimactra  lenticularis, 

ClIIONE  SUCCINCTA, 


Venus  astartleformis, 
Tapes  truncatum, 
Dosinia  ponderosa, 
Lucina  borealis, 

Arca  trilineata. 


The  formation  is  referred  to  tlie  Miocene. 

The  road  from  Griswold’s  to  New  Idria  keeps  along  pretty  near  the 
line  between  the  Tertiary  unaltered  rocks  and  the  metamorphic  Creta¬ 
ceous.  Large  masses  of  the  former  are  seen  in  the  hills  on  the  eastern 
side,  dipping  at  an  angle  of  45°  to  the  north  and  northeast.  A  broad 
belt  of  country  on  this  side  of  the  range  is  evidently  made  up  of  Ter¬ 
tiary  sandstones. 

The  New  Idria  furnace  or  “hacienda”  is  situated  just  within  the 
borders  of  the  metamorphic.  The  sandstones  occur  in  great  force 
along  the  road  from  Griswold’s,  but  we  had  small  opportunities  to  ex¬ 
amine  them  for  fossils.  From  specimens  obtained  a  few  miles  east  of 
the  furnace,  Mr.  Gabb  was  inclined  to  the  belief  that  the  Eocene  period 
of  the  Tertiary  was  there  represented ;  if  so,  it  would  be  the  onl}^ 
locality  in  the  State  where  this  formation  has  been  detected.  Every¬ 
thing  indicates  a  very  considerable  widening  of  the  Tertiary  belt, 
forming  the  eastern  edge  of  the  chain,  as  we  proceed  southwards,  and 
the  mass  of  these  sandstones  appears  to  dip  towards  the  plain  of  the 
San  Joaquin. 

The  top  of  the  San  Carlos  Peak,  which  is  4977  feet  above  the  sea, 
gives  a  fine  view  of  the  structure  and  topography  of  the  region.  The 
peak  appears  to  be  nearly  in  the  centre  of  the  chain  east  and  west,  and 
is  the  highest  point  in  the  Monte  Diablo  range,  with  the  exception  of 
a  ridge  a  short  distance  to  the  south,  which  is  about  250  feet  higher. 
The  chain  is  here  seen  to  be  broken  into  subordinate  ranges,  which 
have  a  direction  nearly  parallel  with  that  of  the  whole  group  taken  to¬ 
gether,  namely,  N.  35°  AV.  The  strike  of  the  strata  in  this  portion 
of  the  range  is  almost  exactly  east  and  west,  magnetic,  or  N.  75° 
W. — S.  75°  E.,  and  the  general  dip  is  to  the  north  and  northeast. 


GEOL.  VOL.  I. — 8 


58 


GEOLOGY  OF  TIIE  COAST  RANGES. 


Three  parallel  ridges  may  he  seen  to  the  east,  the  two  first  of  nearly 
bare  rock,  with  a  little  chaparral;  the  one  next  the  plain  shows  no 
rock,  although  absolutely  bare  of  vegetation.  To  the  west  the  ranges 
of  mountains  are  lofty  and  broken,  and  the  region  occupied  by  them  a 
sterile,  arid,  and  forbidding  one.  These  ranges  are  irregular  and  broken, 
but  they  have  a  general  parallelism  with  the  axis  of  the  chain;  their  sides 
are  often  precipitous  and  worn  into  deep  canons.  The  ridges  nearest 
the  plain  of  the  San  Joaquin  are  the  most  barren,  and  they  are  entirely 
destitute  of  trees ;  the  central  ridges  have  considerable  forest  vegetation 
in  places ;  the  trees  are  chiefly  pines  and  oaks  and  the  white  cedar 
(Librocedrus),  which  is  the  best  timber  in  the  region. 

What  little  life  there  was  in  this  region  at  the  time  of  our  visit  was 
due  to  the  working  of  the  New  Idria  quicksilver  mine,  which,  during 
the  time  of  the  stoppage  of  the  New  Almaden,  in  consequence  of  legal 
difficulties  and  a  judicial  injunction,  was  of  considerable  importance, 
and  the  main  source  of  this  metal  in  the  State.  This  mine  was  discov¬ 
ered,  in  1855,  by  some  persons  who  were  prospecting  for  silver  ore, 
and  who,  having  discovered  a  large  vein  of  chromic  iron,  considered 
their  fortunes  made ;  this  led  to  a  great  excitement  and  the  thorough 
examination  of  the  region,  the  principal  result  being  the  discovery  of 
cinnabar  at  the  New  Idria  Mine.  There  are  several  openings  or  mines, 
extending  over  a  line  about  three  miles  long,  in  a  direction  of  N.  50° 
W.  from  the  San  Carlos  Mine. to  the  New  Idria,  which  are  the  names 
given  to  the  two  principal  workings,  of  which  the  latter  was  much  the 
most  important.  At  the  San  Carlos  Mine,  which  is  a  little  way  from 
the  summit  of  the  peak  of  the  same  name,  the  rock  is  a  whitish  granu¬ 
lar  sandstone,  in  some  places  considerably  metamorphosed,  in  others 
in  almost  its  original  condition.'  The  ore,  cinnabar,  is  most  irregularly 
diffused  through  the  rock,  so  much  so  that  there  is  no  system  or  regu¬ 
larity  to  be  traced  in  the  workings,  which  extend  through  a  little  over 
one  hundred  feet  of  vertical  height,  and  are  scattered  over  several 
square  rods  of  surface. 

The  Aurora  Mine  is  situated  on  the  north  side  of  a  steep  mountain 
side,  about  a  mile  S.  50°  W.  from  the  summit  of  San  Carlos,  and  at  an 
elevation  of  about  1500  feet  above  the  furnace.  The  rock  here  is  an 
exceedingly  hard,  silicious  material,  colored  green  in  places  by  nickel, 


MONTE  DIABLO  RANGE. 


59 


with  ferruginous  portions,  and  a  little  cinnabar  scattered  through  it  in 
specks.  There  is  a  large  amount  of  serpentine  in  this  vicinity,  between 
the  San  Carlos  and  New  Idria  Mines,  and  on  the  ridge  to  the  west.  In 
this  serpentine  occurs  the  deposit  or  bed  of  chromic  iron,  mentioned 
before  as  having  been  mistaken  for  silver  ore.  It  is  near  the  summit 
of  a  ridge,  to  the  west  of  the  canon  running  from  San  Carlos  to  the 
furnace,  and  which  divides  Monterey  and  Fresno  Counties.  The  work¬ 
ings  in  this  deposit  have  all  fallen  in  and  are  covered  by  disintegrated 
serpentine,  but  a  large  amount  of  the  chromic  iron  lies  on  the  surface; 
not  less  than  thirty  or  forty  tons  of  the  pure  material  being  piled  up 
near  the  holes  from  which  it  was  taken.  In  one  place  a  block  of 
chromic  iron,  entirely  free  from  any  admixture  with  the  serpentine, 
projects  from  the  ground  to  a  height  of  four  feet,  and  is  seven  feet  four 
inches  long  and  five  feet  six  inches  wide ;  how  extraordinarily  large  the 

mass  of  ore  must  be,  of  which  this  is  a  projecting  fragment,  is  easily  to 

% 

be  inferred.  The  excavations  were  made  here  under  the  mistaken 
idea  that  this  was  silver  ore,  and  a  furnace  was  erected  for  smelting  it; 
in  the  whole,  many  thousand  dollars  must  have  been  wasted  in  this 
enterprise.  The  locality,  however,  is  very  interesting,  as  being  the 
largest  and  most  important  deposit  of  chromic  iron  known  to  exist  in 
the  State,  and  we  are  not  aware  that  any  locality  has  ever  been  discov¬ 
ered  where  so  large  and  pure  masses  of  this  ore  are  found. 

A  variety  of  interesting  magnesian  minerals  were  obtained  in  this 
vicinity,  including  marmolite,  hydromagnesite,  and  a  fibrous-radiated 
and  concentrically-laminated  variety  of  serpentine,  of  interest  as  show¬ 
ing  the  unquestionably  metamorphic  origin  of  this  substance. 

The  rocks  at  the  New  Idria  Mine  are  very  varied  in  character,  con¬ 
sisting  of  sandstones  and  slates  in  various  stages  of  metamorphism.  In 
these  the  cinnabar  is  very  irregularly  diffused,  and  the  workings  of  the 
mine  are  proportionately  irregular.  The  only  symmetry  which  could 
be  noticed  was  an  apparent  radiation  from  a  centre  of  the  masses  of 
quicksilver-bearing  rock,  and  a  concentric  band  of  ore-ground  connect¬ 
ing  these  radiating  masses,  which  was  in  some  places  very  productive. 
Thus,  in  the  “  Sleeman  Tunnel,”  a  chamber  of  ore  was  opened  running 
nearly  east  and  west  for  a  distance  of  seventy-five  feet,  and  extending 
from  fifteen  to  twenty  feet  below  the  level  of  the  tunnel,  and  to  seventy- 


60 


GEOLOGY  OF  THE  COAST  RANGES. 


live  feet  above  it.  The  sides  of  this  excavation  are  left  very  rough,  as 
if  no  regular  vein  had  been  followed,  showing  here  and  there  occasional 
threads  of  ore  running  oft*  at  right-angles,  and  forming  thin  deposits  on 
the  sides  of  the  joints  by  which  the  rock  is  divided.  The  rock  in  this 
tunnel  is  a  dark,  somewhat  bituminous,  silico-argillaceous  slate,  much 
fractured  and  fissured,  tilled  with  slickensides,  and  so  disturbed  that 
it  would  be  impossible  to  make  out  its  average  dip  and  direction.  An¬ 
other  large  body  of  ore  was  taken  out  from  a  cavity  near  the  one  last- 
mentioned,  running  in  a  northeast  direction,  and  quite  straight,  for  a 
distance  of  one  hundred  and  twenty-five  feet,  and  about  seventy  feet 
high.  Here  the  rock  is  very  silicious  and  broken  up  into  a  sort  of 
breccia,  the  cinnabar  filling  the  spaces  between  the  fragments ;  the 
width  of  the  productive  ground  was  from  two  to  three  feet.  There  is 
a  large  amount  of  iron  pyrites  in  connection  with  the  cinnabar  and 
throughout  the  mine ;  this  readily  decomposes  and  adds  to  the  high 
temperature  of  the  workings.  The  difficulty  of  following  the  ore  is 
everywhere  evidenced  in  this  mine  by  the  irregular  character  of  the 
workings,  which  seem  as  if  almost  entirely  governed  by  chance. 

It  is  stated  that  a  large  deposit  of  cinnabar  occurs  in  a  mountain 
called  the  Picacho,  about  twelve  miles  west  of  Hew  Idria.  Some  at¬ 
tempts  were  making,  or  had  been  made,  at  the  time  of  our  visit,  to 
develop  this  and  etect  a  furnace;  they  do  not  appear  to  have  been 
successful. 

We  have  thus  traced  the  Monte  Diablo  Range  nearly  to  its  southern 
extremity,  and  have  arrived  at  the  point  beyond  which  our  investiga¬ 
tions  have  not  extended  in  this  direction ;  the  little  we  know  of  the 
geology  of  the  Gavilan  Range  which  adjoins  the  region  just  described 
on  the  west,  will  be  most  conveniently  given  in  connection  with  the 
description  of  the  Salinas  Valley  and  the  mountains  to  the  west  of  it, 
as  our  explorations  were  all  made  from  that  side.  Owing  to  the  in¬ 
completeness  of  our  work,  we  must  necessarily  follow  a  somewhat  arbi¬ 
trary  arrangement  in  a  Teport  of  progress;  it  would  only  be  possible  to 
arrange  a  thoroughly  systematic  division  of  the  various  regions  de¬ 
scribed,  after  the  whole  ground  had  been  thoroughly  gone  over  and  a 
much  nearer  approach  to  a  complete  map  of  the  country  obtained, 
than  we  have  now  in  our  power  to  compile. 


T11E  PENINSULA  OF  SAN  FRANCISCO. 


Cl 


CHAPTER  III. 

THE  FENINSULA  OF  SAN  FRANCISCO,  INCLUDING  THE  REGION  FROM 
THE  BAY  OF  MONTEREY  TO  THE  GOLDEN  GATE. 

Having  gone  over  the  geology  of  the  Monte  Diablo  Range  as  com¬ 
pletely  as  our  observations  permit  us  to  do,  it  will  be  convenient  next 
to  take  up  tlie  region  on  the  west  side  of  tlie  Bay  of  San  Francisco  and 
the  Santa  Clara  Valley.  In  doing  this  we  shall  start  at  the  north  end 
of  the  Bay  of  Monterey  and  trace  the  formations  along  the  coast  from 
the  southeast  towards  the  northwest,  thus  following  a  geographical 
order,  and  necessarily  a  somewhat  artificial  one,  as  it  is  impossible  to 
avoid  doing  at  the  present  stage  of  our  work. 

As  on  the  east  side  of  the  hay,  so  on  the  peninsula  bordering  its 
western  shore  and  separating  it  from  the  Pacific  Ocean,  the  hills  and 
mountainous  portions  of  the  surface  predominate  greatly  over  the 
plains.  Mountains  cover  the  whole  region  north  of  the  Bay  of  Monte¬ 
rey,  with  the  exception  of  a  strip  along  the  Bay  of  San  Francisco, 
which  widens  out  as  we  go  south,  commencing  at  Point  'San  Bruno, 
and  which  joins  with  the  Valley  of  Santa  Clara  or  San  Jos6  at  the 
-southern  extremity  of  the  bay.  Along  the  Pacific  coast  the  mountains 
come  close  down  to  the  ocean  ;  or,  at  least,  are  separated  from  it  only 
by  a  narrow  strip  of  table-land.  Portions  of  this  mountain  region,  with 
the  very  narrow  valleys  which  it  includes,  and  especially  the  lands 
along  the  base  of  the  hills  on  the  bay  side,  are  among  the  most  delight¬ 
ful  and  desirable  sites  in  California,  both  on  account  of  soil  and  cli¬ 
mate,  and,  it  may  be  added,  for  picturesque  beauty  of  situation.  San 
Francisco,  the  metropolis  of  the  Pacific  coast,  comprising  fully  one- 
quarter  of  the  population  of  the  State,  and  a  much  larger  proportion  ot 
its  wealth,  stretches  her  arm  down  the  peninsula,  and  the  numerous 
fine  country-seats  along  the  foot-hills,  far  beyond  San  Mateo,  tell  ot  the 
prosperity  of  the  commercial  capital. 

What  has  been  said  of  the  geology  of  the  Contra  Costa  Hills  will  in 
a  considerable  degree  apply  to  the  ranges  on  the  east  side  of  the  bay. 


G2 


GEOLOGY  OF  THE  COAST  RANGES. 


There  are,  on  this  side  as  well  as  that,  a  number  of  parallel  ranges, 
which  extend  for  a  certain  distance  and  then  come  together  into  great 
masses  of  mountains,  in  which  no  definite  trend  of  the  subordinate 
parts  can  be  traced.  For  these  ranges  there  are  no  particular  designa¬ 
tions  in  general  use,  and  it  is  very  difficult  to  give  them  satisfactory 
and  appropriate  names.  Beginning  at  the  north,  however,  we  find  the 
name  “  San  Bruno  Mountains”  given  to  the  short  range  which  extends 
in  a  direction  diagonal  to  the  peninsula  from  Sierra  Point  nearly  across 
to  the  Pacific,  being  separated  by  a  low  divide  from  the  group  of  hills 
on  the  San  Miguel  Bancli,  to  which  the  name  of  San  Miguel  Hills  may 
be  given.  The  ranges  extending  through  San  Mateo  County  and  their 
continuations  through  Santa  Cruz,  may  conveniently  be  designated  by 
the  names  of  the  counties  through  which  they  pass,  since  there  is  no 
general  well-known  name  for  them. 

In  these  hills  and  mountains  of  the  peninsula  we  have  in  many  re¬ 
spects  the  counterpart  of  those  on  the  opposite  side  of  the  bay.  They 
belong  to  the  same  Tertiary  and  Cretaceous  systems,  and  exhibit  the 
same  general  lithological  characters,  yet  with  many  local  peculiarities. 
Fossils  are  much  less  abundant  in  these  ranges  than  in  those  on  the 
Monte  Diablo  side,  and  the  geology  is  rendered  more  complicated  by 
the  presence  of  intrusive  granitic  rocks,  which  appear  in  several  places 
on  the  peninsula. 

The  entire  system  of  elevations  between  the  Bay  of  Monterey  and  the. 
Golden  Gate  is  sometimes  included  under  one  name,  and  called  the 
Santa  Cruz  Bange,  which  is,  however,  properly  the  term  for  the  south¬ 
ern  and  middle  portions  of  the  hills  in  question,  or  those  included  in 
Santa  Cruz  County.  Here,  in  fact,  are  the  highest  mountains  and  the 
broadest  belt  of  elevated  country,  the  chain  diminishing  in  height  and 
breadth  as  it  runs  north,  until  it  finally  sinks  beneath  the  ocean  at  the 
Golden  Gate.  The  entire  range,  from  the  Bay  of  Monterey  to  the  end 
of  the  peninsula,  is  about  sixty-five  miles  in  length,  and  its  greatest 
breadth  is  about  twenty-five  miles.  The  eastern  ridges  are  highly 
metamorphic,  and  constitute  the  main  portion  or  backbone  of  the 
range,  Mount  Bache  being  the  highest  point;  this  has  an  elevation  of* 
3780  feet,  being  less  than  a  hundred  feet  lower  than  Monte  Diablo; 
this  mountain-mass,  to  which  Mounts  Clioual  (3530  feet)  and  Umunhum 


THE  PENINSULA  OF  SAN  FRANCISCO. 


63 

(3430  feet)  belong,  is  the  dominating  one  of  the  range,  although  there 
are  points  farther  north  which  rise  to  over  3000  feet. 

Taking  up  the  description  of  these  mountains,  which  are  collectively 
designated  as  the  Santa  Cruz  Range,  we  commence  near  the  town  of 
that  name  and  proceed  in  a  northerly  direction,  grouping  the  subdi¬ 
visions  of  the  range  in  as  natural  a  manner  as  is  possible. 

In  crossing  over  from  Santa  Cruz,  in  a  northerly  direction  across  the 
chain,  to  the  Santa  Clara  Valley,  before  reaching  the  metamorphic,  a 
mass  of  rocks  is  traversed,  which  is  much  broken  and  elevated,  some 
of  the  ridges  being  fully  2000  feet  high.  In  rising  on  to  this  elevated 
ridge,  however,  we  first  pass  over  a  belt  of  unaltered  strata,  which  near 
the  town  lie  nearly  horizontal,  and  which  appear  to  have  escaped  the 
action  of  the  elevating  forces  by  which  the  main  chain  has  been  raised. 
There  appears  to  be  no  doubt  that  these  horizontal  strata  are  the  same 
ones  which  are  tilted  up  in  the  mountains,  and  that  they  belong  to  the 
Miocene  Tertiary. 

At  about  six  miles  from  Santa  Cruz  are  some  singular  examples  of 
weathered  sandstone,  which  are  known  as  “the  Ruins,”  or  the  “Ruined 
City.”  Here  perpendicular  tubes  or  chimneys  of  rock  are  found,  from 
one  to  three  feet  in  diameter,  the  sandstone  appearing  to  have  been 
hardened  in  concentric  layers  by  the  infiltration  of  ferruginous  solutions, 
and  this  hardened  portion  lias  withstood  the  action  of  the  elements, 
while  the  softer  bands  and  the  interior  columnar  or  cylindrical  masses 
have  weathered  away,  leaving  a  pile  of  rocks  behind,  which,  by  some 
exertion  of  the  imagination,  can  be  construed  into  a  resemblance  to  a 
ruined  city  on  a  very  small  scale,  as  may  be  seen  from  the  annexed 
sketch  (Fig.  6)  of  one  of  the  most  prominent  of  these  castellated  piles. 
These  rocks  contain  quite  a  number  of  fragments  of  echinoderms. 

In  the  more  broken  and  higher  ridges  farther  north,  near  the  summit 
of  the  pass,  the  rock  is  chiefly  sandstone,  in  places  interstratified  with 
slates,  and  at  the  highest  part  of  the  road  these  strata  are  somewhat 
metamorphic. 

^  From  an  elevated  point  near  the  summit  an  extensive  view  was  had 
of  the  southern  part  of  the  range  of  the  high  and  deeply  eroded  ridges  of 
Mount  Baclie,  to  the  east,  and  of  the  ranges  to  the  northeast,  which  are 
also  lofty  and  rugged,  rising  in  some  places  to  nearly  3500  feet  in  eleva- 


G4 


GEOLOGY  OF  THE  COAST  RANGES. 


tion.  The  scenery  on  this  road  from  Santa  Cruz  to  San  Jos£  is  hardly 
surpassed  in  grandeur  and  beauty  by  anything  in  the  Coast  Ranges. 
There  are  heavy  forests  of  pines,  firs  and  oaks,  which  almost  vie  with 


Fig.  6. 


RUINED  CITY,  NEAR  SANTA  CRUZ. 


those  of  the  Sierra  in  size  and  vigor  of  growth.  In  the  Valley  of  the 
San  Lorenzo,  above  Santa  Cruz,  there  are  magnificent  groves  of  red¬ 
wood,  the  finest  which  can  he  seen  within  easy  distance  of  San  Fran¬ 
cisco,  and  well  worth  a  journey  to  examine,  as  they  are  little  inferior 
to  the  Big  Trees  in  size  or  beauty.  One  measured  fifty  feet  in  circum¬ 
ference  at  the  base,  and  is  said  to  be  two  hundred  and  seventy -five  feet 
high,  as  determined  by  the  United  States  linear  surveyors. 

Gold  occurs  on  the  eastern  slope  of  this  ridge,  but  probably  not  in 
paying  quantity,  although  a  considerable  amount  of  ground  has  been 
washed  over. 

The  metamorpliic  belt,  before  spoken  of  as  occurring  on  the  east  side, 
forms  the  highest  ridges  of  the  range.  The  higher  masses  extend  from 


TI1E  PENINSULA  OF  SAN  FRANCISCO. 


Go 


a  point  back  of  Redwood  City,  southeast  for  about  forty  miles.  The 
most  northerly  portion  of  this  metamorphic  ridge  visited  was  that 
which  lies  hack  of  Mountain  View,  and  of  which  Black  Mountain  is 
the  culminating  point,  being  about  3000  feet  high.*  Here  are  several 
parallel  ridges,  having  a  direction  of  about.  N.  54°  W.,  S.  54°  E.,  which 
appears  to  be  nearly  the  strike  of  the  rock;  but  the  stratification  is 
very  obscure,  owing  to  the  metamorphic  character  of  the  rock.  These 
ridges  run  out  into  the  plain  to  the  southeast,  their  strike  taking  them 
to  the  north  of  Mount  Bache,  the  range  being  broken  and  irregular  in 
the  intermediate  region,  where  cut  through  by  the  Los  Gatos  and  Quito 
Creeks.  All  these  ridges  have  steep  slopes,  and  are  very  dry  in  the 
summer  and  covered  on  their  northeastern  sides  with  dense  cha¬ 
parral,  composed  more  exclusively  of  the  A  denostoma  fasiculata ,  or 
“  chamiso,”f  than  were  similar  tracts  farther  south,  where  various  spe¬ 
cies  of  Ceanothus  predominate  in  the  dense,  thorny,  and  almost  impene¬ 
trable  undergrowth,  to  which  the  name  of  “  chaparral”  is  universally 
given.  The  slopes  on  the  southwest  sides  of  the  mountains  were  less 
inhospitable,  being  covered  to  a  considerable  extent  with  wild-oats,  as 
were  also  the  foot-hills.  The  rock  in  the  Black  Mountain  mass  is 
almost  exclusively  metamorphic  sandstone,  with  but  little  serpentine 
or  mica-slate,  scarcely  any  of  either  of  them  being  seen.  At  the  sum¬ 
mit  is  an  outcrop  of  metamorphic  limestone,  very  compact  and  hard, 
but  not  crystalline.  The  foot-hills  in  this  region  extend  several  miles 
into  the  San  Jose  Plains,  and  are  covered  with  a  fertile  soil;  they  form 
some  of  the  most  delightful  and  attractive  farming  lands  of  the  State. 

On  the  northwest  side  of  the  high  metamorphic  ridge  before  spoken 
of  as  forming  the  mass  of  Mounts  Bache,  Clioual,  and  Umunhum,  and 
lying  parallel  with  it,  is  a  lower  ridge  in  which  occur  the  quicksilver 
mines  of  Santa  Clara  County;  the  culminating  point  of  this  lower 


*  This  is  the  Black  Mountain  of  the  United  States  Coast  Survey  ;  the  name  “  Lonm 
Prieta”  is  very  commonly  given  by  the  Spanish-Mexican  population  to  any  high  cliapar- 
ral-covered  point  which  looks  black  in  the  distance.  Mount  Bache  is  one  of  these  “  Black 
Mountains.” 

-j-  Where  the  chamiso  predominates,  the  thick  undergrowth  is  usually  designated  as 
“chamisal:”  the  proper  meaning  of  “chaparral”  is  a  dense  undergrowth  of  shrubby 
oaks. 

GKOL.  VOL.  I. — 0 


6G 


GEOLOGY  OF  THE  COAST  RANGES, 


ridge  is  Mount  Chisnantuck,  which  is  1790  feet  high,  and  there  are 
several  points  in  it  which  rise  to  over  1600  feet. 

A  belt  of  metamorphic  limestone  occurs  in  this  ridge,  and  is  evi¬ 
dently  the  same  as  that  noticed  on  Black  Mountain.  It  is  seen  on  the 
Los  Gatos  Creek,  about  one-fourth  of  a  mile  above  Forbes’s  Mill,  where 
it  has  a  distinct  stratification  and  a  dip  to  the  northeast,  and  is  less 
altered  than  near  New  Almaden.  It  is  seen  again  a  short  distance  above 
the  “  Ban chita,”  about  one  or  one  and  a  half  miles  north  of  the  G  uada¬ 
lupe  Mine,  where  it  is  more  altered,  so  much  so  that  no  dip  or  strike  is 
distinguishable.  Another  locality  noticed  was  half  a  mile  south  of  the 
Guadalupe  Mine,  on  the  west  side  of  the  creek,  where  it  is  quarried 
and  burned  for  lime,  supplying  all  the  mines  of  the  vicinity.  It  crops 
out  again  on  the  same  side  of  the  creek,  about  a  fourth  of  a  mile  above  ^ 
the  Enriquita  Mine;  also  on  the  ridge  stretching  between  Mounts 
Choual  and  Chisnantuck,  where  it  is  distinctly  stratified,  and  contains 
impressions  of  the  scales  of  fishes;  a  whole  fish,  in  an  imperfect  con¬ 
dition,  has  also  been  found  here.  The  rock  at  this  locality  contains 
black  silicious  nodules,  Another  locality  is  about  one  mile  S.  37°  E. 
of  Chisnantuck,  where  it  is  highly  altered  and  no  stratification  visible ; 
from  here  it  may  be  traced  a  mile  and  a  half  farther  to  the  southeast. 
Although  all  these  limestone  masses  appear  evidently  to  belong  to  the 
same  belt,  it  is  not  now  a  continuous  one,  as  it  must  in  all  probability 
have  been  when  first  deposited ;  it  forms  detached  masses,  separated 
from  each  other  by  intervals  of  other  kinds  of  metamorphic  rock.  Iso¬ 
lated  masses  of  limestone  occur  off* the  line  of  this  belt,  on  both  sides; 
one  of  these,  on  the  east  side  of  the  Capitancillos,  between  the  Guada¬ 
lupe  and  the  Enriquita  Mines,  was  quarried  for  burning  into  lime  until 
it  was  exhausted.  The  same  rock  also  occurs  in  patches  between  the 
New  Almaden  Mine  and  the  furnaces,  Other  localities  were  noticed  on 
the  opposite  side  of  the  main  belt,  on  the  ridge  at  the  west  base  of 
Mount  Choual,  near  the  spring. 

The  higher  points  ou  the  outer  ridge  are  composed  of  silicified  shales, 
generally  in  the  form  of  red  jaspers.  These  are  lithologically  identical 
with  the  metamorphic  Cretaceous  of  Monte  Diablo,  so  that  hand  speci¬ 
mens  from  the  two  localities  could  not  be  distinguished.  These  jaspery 
shales  form  the  crest  of  Mount  Chisnantuck,  and  extend  southeast  to- 


’tHfe  PENINSULA  OF  SAN  FRANCISCO. 


67 


wards  the  Uvas  Creek,  and  also  to  the  northwest,  cropping  out  in  a 
pretty  well-defined  belt  near  the  furnaces,  and  passing  near  the  mouth 
of  the  new  tunnel  at  the  New  Almaden  Mine;  the  same  rock  was  also 
traced  along  the  ridge  of  Mine  Hill  for  several  miles.  This  is  the  most 
extensive  development  of  these  jaspers  found,  along  this  belt  of  meta- 
morphic  strata,  although  rocks  of  the  same  character  are  seen  in  many 
places  on  this  line,  in  more  limited  quantity. 

The  quicksilver  mines  are  essentially  in  this  principal  belt  of  altered 
slates,  generally  nearer  its  western  edge,  and  there  are  extensive  beds 
of  serpentine  on  both  sides  of  it,  not  entirely  continuous,  hut  suffi¬ 
ciently  so  to  he  considered  as  one  stratum,  while  isolated  patches  also 
occur  off  the  line. 

Mount  Chisnantuck  is  composed  of  red  and  green  jaspers,  having  an 
eastern  dip,  and  this  rock  extends  uninterruptedly  to  the  furnaces,  con¬ 
taining  some  serpentine.  On  the  east  of  this  is  a  belt  of  serpentine, 
which  runs  by  the  school-house  below  New  Almaden.  On  the  ridges 
between  Canada  de  las  Uvas*  and  Chisnantuck,  are  jaspery  rocks  and 
altered  sandstones,  the  latter  having  occasionally  retained  their  ori¬ 
ginal  conditions,  To  the  west  and  southwest  of  Uvas  Creek  are  high 
ridges  covered  with  dense  chaparral,  which  appear  in  the  distance  to 
be  the  continuation  of  the  metamorphic  belt  of  Mount  Bache.  Be¬ 
tween  the  New  Almaden  and  Enriquita  Mines,  metamorphic  slates 
occur,  and  are  sometimes  a  good  deal  decomposed. 

On  the  ridge  that  extends  back  from  Mine  Hill  to  Mount  Umunlium, 
there  occurs  a  limited  patch  of  unaltered  sandstones,  which  contains  a 
number  of  Pectens  and  other  Tertiary  fossils,  and  which  is  surrounded 
on  all  sides  by  metamorphic  rocks.  This  Tertiary  occupies  the  sum¬ 
mit  of  a  low  ridge,  and  it  appears  to  be  the  remains  of  a  folded  mass 
caught  in  and  compressed  between  the  Cretaceous  strata,  as  a  distinct 
synclinal  structure  was  traced  through  it,  not  without  difficulty,  owing 
to  the  broken  and  metamorphic  character  of  the  surrounding  beds,  in 
which  it  is  almost  impossible  to  distinguish  the  real  lines  of  bedding. 

Although  no  fossils  were  found  in  the  quicksilver-bearing  beds  them¬ 
selves,  we  have  little  hesitation  in  referring  them  to  the  age  of  the  Cre- 


*  Not  to  be  confounded  with  the  Canada  of  the  same  name  near  Fort  Tejon. 


68 


GEOLOGY  OF  THE  COAST  RANGES. 


taceous.  The  jaspery  beds  of  Chisnantuek  are  tlie  exact  counterpart 
of  those  of  Monte  Diablo,  which  we  know  to  be  Cretaceous,  and  those 
of  Mine  Hill,  in  which  are  the  deposits  of  cinnabar,  are  evidently  the 
continuation  of  those  of  Mount  Chisnantuek.  And  as  we  trace  them 
farther  north,  to  the  extremity  of  the  peninsula,  we  find  them  still  re¬ 
taining  the  same  lithological  character,  while  we  have  there  the  evi¬ 
dence  of  fossils  to  prove  them  to  belong  to  the  Cretaceous  epoch.  In 
regard  to  the  geological  position  of  the  cinnabar  deposits  of  California, 
it  may  be  added,  that  this  ore  has  been  found  by  us  in  many  localities, 
and  in  formations  of  nearly  every  age.  It  occurs  in  the  Sierra  Ne- 
vada  and  in  the  southern  part  of  the  State  in  strata  of  Triassic  age,  and 
on  the  eastern  slope  of  the  Sierra,  probably  in  rocks  of  the  same  age.  In 
the  Coast  Ranges  it  has  been  found  in  the  Tertiary;  but,  as  far  as  yet 
known,  there  are  no  large  and  valuable  deposits  except  in  the  Cretace¬ 
ous,  in  which  position  the  localities  which  have  been  discovered,  and 
where  the  ore  is  known  to  exist,  in  small  quantity  at  least,  are  very 
numerous,  extending  in  a  line  with  the  metamorphic  Cretaceous  from 
New  Idria  to  Clear  Lake. 

The  only  mine  of  cinnabar  which  has  been  extensively  worked  in 
the  State,  and  with  large  profit,  is  that  of  New  Almaden ;  indeed,  this 
mine  is  the  second  in  importance  in  the  world ;  it  is  only  inferior  in 
productiveness  to  the  Almaden  Mine  itself,  the  average  monthly  pro¬ 
duce  of  quicksilver  for  the  half  year  ending  December,  1864,  being 
4118  flasks,  or  about  300,000  pounds,  equal  to  over  three  and  a  half 
millions  of  pounds  per  annum*  The  present  capacity  of  the  reduction 
works  is  equal  to  a  production  of  5000  flasks  monthly,  or  four  and  a 
half  millions  of  pounds  per  annum.  With  the  New  Almaden,  the  En- 
riquita  Mine  is  now  united,  and  the  total  production  of  the  two,  since 
July,  1850,  is  given  in  the  published  statements  of  the  company  at 
371,880  flasks,  of  which  the  Enriquita  furnished  10,571  only. 

The  ore  from  which  the  larger  portion  of  this  amount  of  metal  has 
been  taken  occupied  a  series  of  irregular  cavities,  mostly  confined 
within  a  space  about  one  hundred  feet  square  and  extending  down¬ 
wards  for  about  four  hundred  feet.  This  ore-ground  dips  to  the  north 
at  an  angle  of  30°  to  35°,  with  the  formation,  and  the  masses  or  cham¬ 
bers  of  ore  are  scattered  through  it  without  any  approach  to  regularity, 


THE  PENINSULA  OF  SAN  FRANCISCO. 


69 


as  is  shown  by  the  fact  that  there  have  been  times  when  there  was  no 
ore  in  sight  in  the  mine,  in  spite  of  its  great  average  productiveness. 

The  ore-ground  extends  for  some  five  miles  to  the  northwest,  in  the 
line  of  strike  of  the  strata,  and  has  been  opened  and  worked  at  inter¬ 
vals,  although  no  one  locality  has  at  all  approached  in  productiveness 
the  New  Almaden  Mine  itself.  The  Enriquita  Mine,  two  miles  north¬ 
west  of  the  Mine  Hill,  was  opened  in  1859;  hut  was  closed  from  May, 
1861,  to  May,  1863;  it  has  produced  about  1,300,000  pounds  of  quick¬ 
silver,  but  has  not  been  worked  with  profit,  owing  to  the  irregular  dis¬ 
tribution  of  the  ore.  The  same  is  true  of  the  Guadalupe  Mine,  two 
miles  beyond  the  Enriquita,  where,  up  to  1862,  nearly  half  a  million 
of  dollars  had  been  expended  in  prospecting. 

Quicksilver  is  one  of  the  important  articles  of  export  from  California; 
a  large  portion  of  it  (in  1864,  just  one-half)  goes  to  China,  the  re¬ 
mainder  chiefly  to  Mexico  and  the  South  American  States.  The  ave¬ 
rage  amount  shipped  from  San  Francisco  for  the  last  five  years  has 
been  33,168  flasks,  or  nearly  two  and  a  half  million  pounds  per  annum. 

In  passing  from  the  Guadalupe  Mine  to  Forbes’s  Mills,  Tertiary  rocks 
are  seen  in  the  low  foot-hills,  having  a  gentle  dip  to  the  northeast. 
The  relations  of  this  deposit  to  the  metamorphic  were  not  satisfactorily 
made  out;  but  it  appeared  to  rest  unconformably  on  the  edges  of  the 
altered  strata.  The  same  rocks  were  again  observed  near  McCartys- 
ville,  where  they  also  have  a  low  dip  to  the  northeast,  and  in  one  place 
they  were  seen  resting  unconformably  on  the  metamorphic  beds  of  the 
quicksilver-bearing  series.  This  locality  was  about  one  mile  up  the 
canon  from  McCartysville. 

Along  the  Los  Gatos  Creek,  above  Forbes’s  Mill,  towards  Lexington, 
the  rock  is  entirely  metamorphic,  often  much  contorted,  and  in  places 
broken  into  angular  fragments,  but  the  large  masses  dip  to  the  north¬ 
east  ;  these  rocks  evidently  belong  to  the  metamorphic  mass  of  Mount 
Bache  and  Black  Mountain.  From  observations  made  in  two  places, 
where  it  was  crossed,  and  as  seen  from  the  heights  between  Los  Gatos 
Creek  and  Black  Mountain,  this  belt  appears  not  to  be  over  three  or 
four  miles  wide.  The  general  dip  of  the  mass  appears  to  be  everywhere 
to  the  northeast.  Up  the  canon  from  McCartysville,  this  rock  was  ob¬ 
served  in  several  places  to  have  a  strike  of  X.  65°  AM,  and  to  dip  at  a 


70 


GEOLOGY  OF  THE  COAST  RANGES. 


high  angle  to  the  north.  Fossils  are  reported  to  occur  on  the  old  trail 
from  Lexington  to  Forbes’s  Mill;  they  are  probably  in  the  unaltered 
Tertiary,  resting  unconformably  on  the  metamorphic,  as  was  seen  near 
McCarty  sville. 

4/ 

Along  the  west  side  of  this  metamorphic  belt  there  is  a  series  of  high 
ridges  of  unaltered  Tertiary  strata.  These  form  a  broad  range  of 
mountains,  extending  from  near  the  summit  of  the  road  from  Santa 
Cruz  to  Lexington,  northwest  into  San  Mateo  County,  and  covering  a 
region  but  little  explored  and  hardly  inhabited.  This  ridge  is  very 
much  furrowed  by  canons,  especially  on  the  southwest  side,  from 
which  flow  the  tributaries  of  the  San  Lorenzo  Creek,  and  the  whole 
region  to  the  west  of  it,  as  far  as  the  Ocean,  is  a  labyrinth  of  hills  and 
canons.  There  are  some  ranches  along  the  coast,  and  settlements  have 
extended  themselves  some  way  up  the  San  Lorenzo  and  Pescadero 
'Creeks;  but  all  the  interior  of  the  mass  of  hills  is  otherwise  uninha¬ 
bited,  and  not  traversed  by  any  trails,  between  the  one  leading  from 
Pescadero  over  to  the  Corte  de  Madera  Ranch,  and  the  road  which 
crosses  from  Santa  Cruz  over  the  mountain  to  Santa  Clara  Valley. 
The  culminating  point  of  this  ridge  lies  about  five  miles  a  little  south 
of  west  from  McCartysville,  and  rises  to  the  height  of  3269  feet  above 
tide.  In  the  absence  of  any  name  for  this  mountain,  it  was  called 
Mount  Bielawski.*  Another  point  two  miles  southeast  of  this  was 
found  to  be  2886  feet  high ;  and  a  third,  four  miles  farther  on,  in  the 
same  direction,  2431  feet  high. 

In  passing  up  the  Los  Gatos  Creek  to  explore  this  region,  shales 
were  met  with  in  the  bed  of  the  creek,  near  Howe’s  Mills,  standing 
vertical,  or  having  a  high  dip  to  the  northwest ;  but  their  strike  was 
observed  to  be  more  east  and  west  than  the  general  direction  of  the 
mountain  mass.  Large  bodies  of  strata  were  seen  with  a  strike  of  N. 
45°  W.  to  A.  55°  W.  Sandstones  were  the  most  abundant  rock  seen 
here,  but  shales  were  often  met  with,  especially  in  the  low  divides. 

The  region  to  the  northwest  of  the  mountain  range  just  noticed, 
and  west  of  Black  Mountain,  including  the  Corte  de  Madera  Ranch  and 


*  In  honor  of  the  chief  draughtsman  of  the  Surveyor-General’s  Office,  Mr.  C.  Bie¬ 
lawski. 


TI1E  PENINSULA  OF  SAN  FRANCISCO. 


71 


the  country  from  there  west  to  Pescadero,  was  also  traversed  and  some 
examinations  made.  About  Searsville  there  are  some  exposures  of  meta- 
morpliic  sandstone,  and  between  there  and  Redwood  City  a  light  brown 
sandstone  was  noticed,  in  which  Mr.  Gabb  detected  a  fucoid,  similar  to 
one  observed  in  the  beds  of  Cretaceous  rock  overlying  the  coal  at 
Monte  Diablo.  From  Searsville,  a  metamorphic  rock,  principally  an 
altered  conglomerate,  containing  large  pebbles  of.  jasper,  continues 
along  the  road  to  a  little  beyond  the  southern  boundary  of  the  Corte 
de  Madera  Ranch.  A  portion  of  this  conglomerate  has  escaped  the 
metamorphic  action,  as  boulders  of  this  rock,  unaltered,  were  found  in 
the  San  Francisquito  Canon,  which  were  said  to  have  come  from  just 
below  the  coal ;  but  it  was  not  found  in  place.  This  rock  closely  resem¬ 
bles  a  conglomerate  observed  in  the  Monte  Diablo  Range,  a  little  north 
of  Pacheco’s  Pass,  and  which  is  there  found  in  various  stages  of  alter¬ 
ation. 

The  boundary  between  the  unaltered  and  the  metamorphic  rocks  ex¬ 
tends  along  the  west  side  of  the  ridge,  in  which  the  “  coal-mine”  is 
situated,  although  the  exact  line  of  contact  is  concealed.  In  a  side- 
canon,  about  a  mile  northwest  of  the  mine,  and  running  from  the  next 
ridge  to  the  west,  the  Cretaceous  shales  crop  out  in  a  few  small  expo¬ 
sures  at  the  base  of  the  hill;  here  the  strike  is  ~N.  42°  W.,  and  the  dip 
about  45°  to  the  northeast.  The  upper  portion  of  this  ridge  is  made 
up  of  a  highly  fossiliferous  shale,  with  some  sandstone,  which  rocks 
are  of  Tertiary  age,  and  are  referred  to  the  Miocene  by  Mr.  Gabb.  In 
the  bed  of  the  creek  were,  among  the  boulders  of  sandstone,  some  frag¬ 
ments  of  syenitic  granite  and  of  a  basaltic  rock,  which  latter  is  said  to 
cap  a  few  of  the  highest  points  of  this  ridge. 

The  “  coal-mine”  is  just  on  the  edge  of  the  metamorphic  strata,  and 
in  the  excavations  made  there  considerable  masses  of  lignite,  showing 
the  original  fibre  and  annual  rings  of  the  wood,  have  been  found. 
From  the  workings  a  gray,  sandy  clay  has  been  taken,  which  contained 
some  fossil  shells  and  a  few  impressions  of  leaves,  too  imperfect  for 
determination. 

Quite  extensive  “prospecting”  has  been  carried  on  here  for  coal,  and 
also  for  quicksilver,  on  the  opposite  side  of  the  ridge,  in  the  metamor¬ 
phic  rocks.  There  was  a  shaft  sunk  to  the  depth  of  seventy-five  feet 


72 


GEOLOGY  OF  THE  COAST  RANGES. 


in  a  vein  or  bed  of  red  clay,  which  was  said  to  contain  cinnabar,  but 
there  was  none  of  this  metal  or  its  ore  visible  to  the  eye  ;  it  was  stated, 
however,  that  assays  made  of  this  material  had  given  from  three  to  ten 
per  cent,  of  quicksilver.  There  are  several  veins  of  this  red  clay,  close 
together  and  varying  from  a  few  inches  to  a  foot  and  a  half  in  thick¬ 
ness.  The  formation  is  one  in  which  this  metal  might  be  found;  but 
if  the  clay  contained  more  than  a  trace  of  cinnabar,  it  would  be  a  dif¬ 
ferent  mode  of  occurrence  of  this  ore  from  any  that  we  have  hitherto 

t 

observed  in  California. 

Following  the  same  ridge  to  the  south,  the  conglomerate  becomes 
covered  with  soil,  and  before  reaching  the  highest  point  of  the  road  ex¬ 
posures  of  Tertiary  rocks  are  met  with.  The  first  of  these  is  of  a  light- 
colored  sandstone  without  fossils;  but  a  little  farther  on  is  a  white  sand¬ 
stone  full  of  irregular  grains  of  calcareous  spar.  This  rock  is  highly 
fossiliferous,  containing  shells  belonging  to  the  genera  most  commonly 
found  in  the  Miocene  Tertiary  of  the  Coast  Ranges,  such  as  Mytilus , 
Pallium ,  Pecten ,  Venus ,  and  the  large  oyster  ( Ostrea  Titan)  so  abundant 
and  characteristic  of  this  division  of  the  series. 

From  tins  point  to  Lambert’s,  sandstones  and  shales  occur,  but  no 
fossils  were  observed.  The  hill  west  of  Lambert’s  consists  of  a  light- 
brown  unaltered  sandstone  on  the  summit  and,  so  far  as  was  seen,  on 
the  east  side.  On  the  west  side,  however,  fragments  of  shales  and 
limestones  resembling  those  of  the  Cretaceous  formation  were  ob¬ 
served  ;  but  these  rocks  were  not  found  in  place.  In  a  hill  two  and  a 
half  miles  southeast  of  Lambert’s,  shales  and  sandstones  were  also 
seen,  but  apparently  not  of  Cretaceous  age.  In  the  “  Devil’s  Canon” 
there  is  a  fine  exposure  of  sandstone,  overlaying  the  shales  just  men¬ 
tioned,  and  having  a  strike  to  the  northwest,  and  a  dip  of  55°  to  the 
southwest. 

In  the  region  to  the  southwest  of  the  Tertiary  and  metamorphic  Cre¬ 
taceous  belt  which  has  just  been  described  as  extending  along  from 
Mount  Baclie  to  Searsville,  and  forming  the  centre  and  eastern  edge  of 
the  Santa  Cruz  Range,  there  is  a  high  range  of  granite  hills,  of  which 
the  southern  termination  is  near  the  town  of  Santa  Cruz,  and  where  a 
great  deal  of  prospecting  for  gold  has  been  done.  It  is  stated,  on 
what  is  believed  to  be  good  authority,  that  at  least  one  quite  rich  mass 


THE  PENINSULA  OF  SAN  FRANCISCO. 


of  auriferous  veinstone  lias  been  obtained  here.  There  does  not,  how¬ 
ever,  seem  to  be  any  prospect  of  permanent  profitable  working  for  this 
metal  at  this  point,  as  no  well-defined  vein  could  be  traced. 

This  ridge  of  granite  extends  oft*  to  the  northwest  from  Santa  Cruz, 
but  disappears  before  reaching  Pescadero  Creek.  Its  highest  point 
is  between  2800  and  2900  feet  in  elevation.  Unfortunately  the  op¬ 
portunities  for  observing  the  relations  of  this  rock  to  the  surrounding 
strata  are  very  poor.  The  coast  was  followed  up  from  Santa  Cruz  to 
Pescadero  by  our  party,  and  some  examinations  made  inland.  Along 
the  trail  travelled  to  the  mouth  of  Scott’s  Creek,  there  are  numerous 
outcrops  of  bituminous  shale,  always  horizontal,  or  so  nearly  so  as  to 
indicate  that  no  disturbance  has  taken  place  in  this  rock  since  its  de¬ 
position.  About  eight  miles  from  Santa  Cruz,  near  the  road,  on  a 
small  creek,  a  bed  of  coarse  gray  sandstone  was  seen,  which  is  curi¬ 
ously  weathered  into  small  irregular  cavities  over  its  entire  surface. 
This  bed  is  horizontal,  intercalated  in  the  bituminous  shale,  and  from 
twenty-five  to  thirty  feet  thick;  it  was  destitute  of  fossils.  An  attempt 
was  made  to  ascend  the  granite  ridge  from  Scott’s  Creek,  but  it  was 
not  reached,  on  account  of  the  thickness  of  the  chaparral.  A  high 
point  was  attained,  however,  which  was  made  up  of  white  shale  or 
slate,  with  a  very  gentle  dip  of  about  8°  in  a  direction  a  little  south  of 
west  and  away  from  a  high  ridge  just  west  of  the  San  Lorenzo  Creek; 
this  ridge  appeared  to  be  of  granite,  as  boulders  of  this  rock  were  seen 
in  the  creeks  at  its  base. 

Just  north  of  the  Hew  Year’s  Point  ranch  house,  an  exposure  is  seen 
in  the  bluffs,  on  the  coast,  of  fine-grained  sandstone,  referred  by  Mr. 
Gabb  to  the  Pliocene.  This  deposit  seems  to  form  a  small  basin,  cut 
through  by  the  coast-line,  and  extending  for  about  a  mile  along  the 
shore. 

At  Pigeon  Point,  a  bluish-gray,  very  compact  sandstone  was  found, 
containing  Natica ,  Mactra ,  and  Mytilus ,  and  belonging  to  the  great 
Miocene  Tertiary  of  this  portion  of  the  peninsula.  The  coast,  for 
nearly  the  whole  distance  between  Pescadero  and  Santa  Cruz,  shows 
two  well-marked  terraces,  of  variable  height,  and  often  interrupted  by 
the  coming  down  of  the  hills  quite  to  the  shore.  The  whole  region 
traversed  by  the  trail  from  Pescadero  to  Searsville,  as  far  as  the  meta- 

GEOL.  VOL.  I. — 10 


74 


GEOLOGY  OF  THE  COAST  RANGES. 


morphic  on  tlie  eastern  edge  of  the  range,  is  bituminous  shale  of  Mio¬ 
cene  age,  with  occasional  beds  of  interstratified  sandstone,  of  which  the 
dip  is  irregular  but  not  high. 

From  Lambert’s  along  the  ridge  north  of  Pescadero  Creek,  the  rock 
is  a  shale  or  slate,  of  a  light  cream-color  passing  into  gray.  It  contains, 
towards  the  east,  occasional  seams  of  sandstone,  which  disappear 
within  a  few  miles  of  Lambert’s.  The  general  strike  of  these  strata  is 
nearly  northwest  and  southeast;  they  have  a  dip  which  indicates  that 
the  surface  has  been  thrown  into  a  series  of  low  arches  since  the  depo¬ 
sition  of  this  bituminous  shale.  No  other  fossils  were  found  than  a 
few  small  splinters  of  opalized  wood  and  an  impression  of  a  fish-scale; 
but,  from  lithological  characters  and  general  position,  it  can  hardly  be 
anything  else  than  the  Miocene  bituminous  slate  of  the  Coast  Ranges. 
The  same  rock  is  seen  in  the  high  hills  between  the  Pescadero  and 
Butano  Creeks,  and  near  the  beach  west  of  Pescadero;  going  north 
from  the  last-named  place  it  continues,  as  far  as  three  miles  northeast 
of  Spanish  Town,  where  it  caps  a  mass  of  granite  which  forms  the 
body  of  the  ridge. 

Another  line  of  section  across  the  peninsula  was  examined,  namely, 
from  San  Mateo  to  Half-Moon  Bay,  at  Spanish  Town. 

Near  San  Mateo,  and  a  little  to  the  north  of  the  road  to  Crystal 
Springs,  there  is  a  good  exposure  of  the  metamorphic  rock  which  forms 
the  eastern  edge  of  the  mountain  belt  of  the  peninsula.  The  rock  here 
is  a  red  jaspery  mass,  quite  resembling  that  of  Monte  Diablo,  distinctly 
stratified,  and  passing  into  brown  argillaceous  sandstone ;  it  'dips  east, 
at  an  angle  of  ,  35°.  As  we  proceed  west  along  the  Crystal  Springs 
road,  the  ground  rises  and  finally  assumes  the  form  of  a  rolling  pla¬ 
teau,  of  which  the  summit  is  about  1200  feet  high.  In  thus  passing 
west,  the  rocks  become  more  and  more  metamorphic,  and  serpentine 
makes  its  appearance.  On  the  ridge  fronting  San  Andreas  Creek,  to 
the  north  of  Crystal  Springs,  there  is  serpentine,  intermixed  with  white 
quartz,  and  red  and  green  jaspers. 

In  the  canon  of  the  San  Andreas,  on  the  west  side,  there  is  a  heavy 
mass  of  limestone,  which  may  be  traced  high  up  in  the  side  gorges 
coming  down  from  the  west.  It  dips  to  the  northeast,  at  a  varying 
angle,  usually  not  less  than  35°,  but  in  some  places  stands  nearly  ver- 


tieal.  The  upper  layers  are  thin-bedded,  and  some  strata  are  light- 
colored,  others  dark;  below,  the  stratification  is  less  distinct,  the  layers 
heavier,  and  the  rock  more  crystalline.  The  thickness  of  this  belt  of 
limestone  must  be  over  1000  feet;  but  it  was  not  seen  in  its  full  width. 
A  little  distance  south  of  Crystal  Springs,  this  rock  was  formerly  quar¬ 
ried  and  burned  for  lime. 

Between  the  limestone  mass  and  the  head  of  Pilarcitos  Creek,  there 
is  a  series  of  heavy-bedded  sandstones,  brown  in  color,  but  so  much 
broken  and  so  irregular  that  their  position  could  not  be  made  out, 
although  they  appeared  in  some  places  to  be  conformable  with  the 
limestone  belt,  which  dips  to  the  east.  This  sandstone  forms  a  ridge, 
which  rises  to  about  2500  feet  above  the  sea,  and  is  the  backbone  of 
the  peninsula  in  this  region,  occupying  a  belt  of  high  rolling  country 
for  two  or  three  miles  in  width.  No  fossils  could  be  found  in  this  rock. 

West  of  this  is  a  range  of  granitic  hills,  to  which  the  Cumbre  de  las 
Auras  belongs,  and  which  runs  northwest  and  dies  out  just  before 
reaching  Point  San  Pedro.  This  granitic  mass  occupies  an  elliptical 
area,  and  consists  of  high,  rounded,  almost  bare  ridges,  rising  in  their 
highest  peaks  from  2500  to  3000  feet  above  the  sea.  The  granite 
decomposes  readily,  and  the  sides  of  the  hills  are  in  places  covered  by 
heavy  masses  of  disintegrated  rock.  The  region  is  dry  and  unculti¬ 
vated. 

Beyond  this,  to  the  west,  is  first  a  low  ridge  of  heavy-bedded  friable 
sandstone,  with  a  dip  of  40°,  away  from  the  granite,  or  to  the  west; 
proceeding  a  little  farther  west-,  however,  the  same  strata  are  seen 
again  with  an  easterly  dip  of  50°,  and  this  continues  to  be  the  direction 
of  the  dip  all  the  way  to  the  sandy  plain  on  which  Spanish  Town  is 
built.  The  strata,  however,  have  a  less  and  less  decided  inclination  as 
we  recede  from  the  granite,  and  finally,  before  reaching  the  coast,  be¬ 
come  nearly  horizontal;  they  also  pass  gradually  from  sandstones  to 
shales,  very  thinly-bedded  and  a  good  deal  broken.  The  fossils  found 
in  these  strata  show  that  they  belong  to  the  Miocene  Tertiary.  They 
are  the  continuation  of  the  bituminous  slate  series  which  extends  all 
along  the  coast  from  Santa  Cruz  to  Spanish  Town,  forming  a  gradually 
narrowing  belt  of  rock,  which  is  slightly  disturbed  near  the  granite; 
but,  at  a  little  distance  from  it,  retains  its  original  position. 


76 


GEOLOGY  OF  THE  COAST  RANGES. 


The  belt  of  limestone  noticed  above,  as  occurring  between  San  An¬ 
dreas  and  San  Mateo  Creeks,  runs  out  to  the  sea-sliore  about  one  and 
a  quarter  miles  north  of  Point  San  Pedro,  forming  a  low  ridge  or  head¬ 
land.  Here  it  has  to  the  south  of  it  a  red  and  green  jaspery  rock,  dis¬ 
tinctly  stratified,  and  having  the  same  northeasterly  dip  as  the  lime¬ 
stone.  The  granite  range  of  the  Cumbre  de  las  Auras  disappears 
beneath  the  ocean,  but  rises  again  to  the  north  of  the  Golden  Gate,  in 
the  promontory  of  Punta  de  los  Reyes. 

The  great  regular  ranges  of  mountains  which  form  the  peninsula 
appear  to  run  out,  to  the  north  of  San  Pedro,  and  no  more  granite  is 
seen  on  its  northern  end  after  passing  the  mass  of  the  Cumbre  de  las 
Auras.  The  extremity  of  the  peninsula  is  occupied  by  short  and 
broken  ranges,  or  low  hills,  in  which  the  regular  trend  to  the  northwest 
can  be  no  longer  detected,  but  where  the  influence  of  the  east  and  west 
line  of  depression,  by  which  the  Golden  Gate  has  been  opened,  and  ac¬ 
cess  given  to  the  interior,  is  manifested  in  the  most,  chaotic  jumble  of 
strata  which  it  is  possible  to  find  in  the  State. 

The  larger  portion  of  the  rocks  which  make  up  the  north  end  of  the 
peninsula  are  of  Cretaceous  age,  and  are  more  or  less  metamorphic  in 
character,  being  in  fact  the  continuation  of  the  strata  which  form  the 
eastern  edge  of  the  belt  of  mountains,  which  have  just  been  noticed  as 
extending  through  Santa  Cruz  and  San  Mateo  Counties.  The  princi¬ 
pal  varieties  are  the  brown  argillaceous  sandstone,  in  all  stages  of  pas¬ 
sage,  from  the  entirely  unaltered  rock  to  the  hard,  dark-colored,  almost 
dioritic  material ;  then  the  metamorphic  shales,  or  the  silicious  slates 
passing  into  jaspery  rock,  as  is  so  often  seen  in  the  metamorphic  Cre¬ 
taceous.  Besides  these,  which  make  up  the  greater  portion  of  the  sur¬ 
face  in  this  region,  there  are  large  masses  of  serpentine  and  occasional 
beds  of  the  peculiar  locally-metamorphosed  silicious  rock,  which  is  so 
often  accompanied  by  ores  of  mercury.  There  are  no  eruptive  rocks 
on  the  peninsula,  to  the  north  of  San  Mateo,  so  far  as  our  observations 
extend. 

Owing  to  the  near  approach  of  the  rocky  hills  to  the  shore,  and  the 
great  number  of  points  where  the  ocean  has  cut  into  them,  there  is  no 
lack  of  good  exposures  of  the  strata  in  the  vicinity  of  San  Francisco. 
Extensive  artificial  excavations  within  the  city  for  opening  new  streets 


THE  PENINSULA  OF  SAN  FRANCISCO. 


77 


have  also  furnished  excellent  sections  of  the  rocks,  at  a  heavy  expense 
to  the  property-holders.  But,  so  crushed  and  broken  are  the  strata 
thus  revealed  to  view,  and  so  few  and  indistinct  the  fossils  which  they 
contain,  that  it  was  a  long  time  before  their  real  age  could  be  clearly 
made  out,  and  it  was  not  until  after  we  had  decided,  on  stratigraphical 
and  lithological  grounds,  that  the  so-called  “  San  Francisco  sandstone” 
must  be  of  Cretaceous  age,  that  the  timely  discovery  of  a  single  shell, 
undoubtedly  of  this  epoch,  in  the  rocks  of  Alcatraz  Island,  gave  the 
additional  desirable  assurance  of  the  correctness  of  our  views.  We 
now  feel  justified  in  asserting  that  the  whole  of  the  upper  end  of  the 
peninsula,  with  the  exception  of  a  few  patches  of  limited  extent  on  the 
western  side,  belongs  to  the  Cretaceous  epoch. 

Where  least  metamorphosed,  the  Cretaceous  sandstone  is  distinctly 
seen  to  be  made  up  of  fine  rounded  grains  of  silicious  material,  ce¬ 
mented  together  by  carbonate  of  lime.  Its  color  is  a  decided  grayish- 
blue  in  the  interior  of  the  strata;  but  on  the  surface  of  beds  which  have 
been  exposed  to  the  weather  it  is  a  yellowish-brown,  from  the  decom¬ 
position  of  the  protoxide  of  iron  which  appears  to  be  contained  in  the 
cement  which  holds  the  particles  together.  This  rock  is  quarried  to  a 
considerable  extent  as  a  building  material,  especially  on  Angel  Island ; 
it  is  used  chiefly  for  purposes  where  beauty  and  strength  are  not  abso¬ 
lutely  required,  for  this  rock  possesses  neither  qualification  in  a  high 
degree,  although  it  answers  very  well  for  ordinary  uses  in  the  mild  and 
equable  climate  of  San  Francisco.  At  the  quarries  on  Angel  Island, 
the  rock  is  very  heavy-bedded,  and  so  intersected  by  joints  that  it  was 
extremely  difficult  to  make  out  the  real  position  of  the  strata.  The 
dip  appeared,  however,  to  be  to  the  northwest,  at  an  angle  of  65°. 
The  sandstone  on  the  islands  about  the  city  is  more  silicious  and  better 
adapted  for  a  building-stone  than  that  on  the  main-land;  the  quarries 
on  the  islands  have  also  greater  advantages  of  approach,  and  superior 
facilities  of  working. 

The  rock  on  the  main-land  in  and  about  the  city  of  San  Francisco  is 
what  may  be  called  an  argillaceous  sandstone,  that  is  to  say,  a  rock 
formed  from  a  deposit  of  sand  and  mud  intermixed.  Many  portions 
of  it  are  made  up  of  thin  layers  of  silicious  material,  with  shaly  part¬ 
ings  between  them,  while  other  portions  are  rather  homogeneous  in 


78 


GEOLOGY  OF  THE  COAST  RANGES. 


texture  and  heavy-bedded.  Most  of  it  decomposes  gradually  on  expo¬ 
sure,  and  lienee  has  hut  little  value  as  a  building-stone.  Through  much 
of  this  rock  metamorphism  has  hardly  proceeded  farther  than  the  lirst 
stage,  which  is  one  as  much  of  mechanical  preparation  as  of  chemical 
action,  the  strata  having  been  so  broken  up  as  to  allow  the  easy  access 
of  moisture  and  air  from  above,  and  hence  the  rock  is  pretty  thoroughly 
decomposed  to  a  considerable  depth.  This  kind  of  slightly  metamor¬ 
phosed  sandstone  is  well  seen  in  the  excavations  around  Telegraph 
Hill,  of  which  it  forms  the  mass,  and  also  in  the  high  ridge  of  which  Rus¬ 
sian  and  Clay  Street  Hills  form  a  part.  The  more  silicious  and  thinner- 
bedded  layers,  so  peculiar  to  the  Cretaceous  series,  are  well  seen  about 
the  end  of  Rincon  Point,  and  thence  to  Steamboat  Point.  These 
thinner  strata  often  show,  by  the  intricacy  and  closeness  of  their  fold¬ 
ings,  how  thorough,  as  well  as  how  irregular,  the  action  of  the  uplifting 
forces  has  been  in  this  region. 

The  serpentinoid  rocks  occupy  much  less  space  around  the  city  of 
San  Francisco  than  do  the  less  metamorphosed  sandstones.  They  re¬ 
semble  the  masses  of  this  material  which  occur  elsewhere  so  frequently 
in  connection  with  the  Cretaceous  sandstones,  as  has  already  been  fre¬ 
quently  noticed  in  describing  the  geology  of  the  Monte  Diablo  Range. 
The  principal  outcrop  of  this  rock  in  the  neighborhood  of  San  Fran¬ 
cisco  extends  across  from  Fort  Point,  by  Lone  Mountain  and  Mission 
Dolores,  to  the  Potrero.  The  material  known  as  the  “  red  rock,”  and 
which  is  so  much  used  for  ballasting  the  roads  about  the  city,  is  appa¬ 
rently  an  imperfect  serpentine.  A  chemical  examination  of  these  rocks, 
in  their  various  stages  of  progress  from  the  unaltered  to  the  thoroughly 
metamorphosed  material,  is  much  to  be  desired.  A  map  of  the  city 
and  its  vicinity,  on  a  large  scale,  has  been  commenced  by  the  Survey, 
on  which  all  the  varieties  of  strata  and  of  the  superficial  covering  of  • 
soil  and  sands  will  be  laid  down. 

Considerable  patches  of  the  quicksilver-bearing  rock  occur  in  the 
hills  around  the  Mission,  and  both  the  native  metal  and  the  sulphuret 
(cinnabar)  have  been  found  in  small  quantities;  but  no  workable  de¬ 
posit  has  yet  been  discovered.  The  only  other  mineral  of  economical 
value  found  in  the  metamorpliic  Cretaceous  of  this  vicinity  is  the  oxide 
of  manganese  (pyrolusite),  which  has  been  obtained  in  considerable 


THE  PENINSULA  OF  SAN  FRANCISCO. 


79 


quantity  and  in  a  high  degree  of  purity  on  Red  Rock,  near  Point  San 
Pablo,  and  which  also  occurs  on  the  main-land  near  Hunter’s  Point. 
If  extensi  ve  deposits  of  this  mineral  can  be  found,  they  will  be  of  great 
value  to  the  State. 

Although  the  Miocene  Tertiary  sandstones  which  form  so  conspicu¬ 
ous  a  member  of  the  Coast  Ranges  are  not  exposed  in  the  vicinity  of 
San  Francisco,  there  are  somewhat  extensive  outcrops  of  rocks  of  a 
later  Tertiary,  in  the  low  hills  extending  along  the  sea-sliore  southwest 
of  Merced  Lake,  nearly  as  far  as  Mussel  Rock.  According  to  the  ob¬ 
servations  of  Messrs.  Remond  and  Gabb,  there  are  two  sets  of  strata 
here,  which  belong  to  the  Pliocene  and  Post-Pliocene  epochs,  and 
which  are  unconformable  with  each  other.  Both  these  formations 
rest  also  unconformably  on  the  metamorpliic  Cretaceous,  as  does  also 
the  Miocene  in  the  region  north  of  the  Golden  Gate,  while  that  forma¬ 
tion  appears  to  be  wanting  throughout  the  northern  end  of  the  penin- 
sula  of  San  Francisco. 

The  Pliocene  beds  between  Merced  Lake  and  Mussel  Point  are 
made  up  of  a  bluish  sandstone,  of  which  the  grains  are  cemented  by  car¬ 
bonate  of  lime,  interstratified  with  hard,  tine  conglomerates,  of  which 
the-  pebbles  are  evidently  derived  from  the  adjacent  jaspery  rocks  of 
Cretaceous  age.  These  strata  contain  Scutella  inter lineata,  Crejndnla  pr bi¬ 
ceps,  both  of  which  are  extinct,  together  with  several  species  still  living 
on  this  coast.  The  Post-Pliocene  series  consists  of  beds  of  gravel,  sand, 
and  clay,  with  some  soft  sandstones,  and  contains  only  shells  of  recent 
species,  among  which  the  genera  Tellina ,  Mytilus ,  and  Buccinum  are 
represented.  Of  these  two  sets  of  beds,  the  lower,  according  to  Mr. 
Remond,  have  a  northwest  strike,  and  dip  to  the  northeast  at  an  angle 
of  35°,  while  the  upper  ones  have  an  inclination  of  only  10°.  This  is 
only  one  of  a  numerous  class  of  facts,  which  show  that  there  have 
been  quite  extensive  disturbances  of  the  rocks  along  the  coast  within 
a  very  recent  geological  epoch. 


80 


GEOLOGY  OF  THE  COAST  RANGES 


CHAPTER  IV. 

THE  COAST  RANGES  NORTH  OF  THE  BAY  OF  SAN  FRANCISCO. 

In  continuing  our  sketch  of  the  geology  of  the  region  adjacent  to  the 
Bay  of  San  Francisco,  it  remains  for  us  to  take  up  that  portion  of  the 
Coast  Ranges  which  lies  north  of  the  Bays  of  San  Francisco,  San  Pablo, 
and  Suisun.  Owing  to  various  causes,  among  which  want  of  time  was 
the  most  important,  we  have  not  extended  our  explorations  in  this 
direction  beyond  Clear  Lake,  the  geology  of  the  extensive  area  com¬ 
prised  in  Mendocino  and  Humboldt  Counties,  and  belonging  to  the 
Coast  Ranges,  being  only  known  to  us  from  the  examination  of  a  few 
specimens  furnished  to  the  Survey  by  chance  collectors,  and  from  rea¬ 
soning  on  general  principles  of  stratigraphy,  based  on  our  information 
with  regard  to  the  geology  of  the  Coast  Ranges,  by  the  aid  of  which 
we  are  enabled  to  form  a  tolerably  correct  idea  of  what  formations  we 
may  expect  to  find  in  that  region,  whenever  we  have  the  opportunity  of 
exploring  it.  The  little  we  have  to  say  in  regard  to  the  most  northern 
portion  of  the  Coast  Ranges,  or  that  lying  between  Trinity  River  on 
the  east  and  the  Pacific  Ocean  on  the  west,  may,  therefore,  be  conve¬ 
niently  given  in  another  chapter;  in  this  we  shall  take  up  the  region 
immediately  north  of  the  bay,  including  Marin,  Sonoma,  Napa,  Solano, 
Yolo,  Colusi,  and  Lake  Counties. 

In  its  general  features  this  part  of  the  State  resembles,  both  geologi¬ 
cally  and  topographically,  that  region  which  has  just  been  described  as 
forming  the  northern  extension  of  the  Monte  Diablo  and  Santa  Cruz 
Ranges.  We  have  on  the  north  of  the  hay,  as  on  the  south,  the  same 
predominance  of  hill  and  mountain  over  plain  and  valley,  the  same 
parallelism  of  general  trend,  and  the  same  intricacy  of  detail  in  the 
minor  features  of  the  topography.  There  is  no  one  valley  to  the  north 
of  the  bay  which  spreads  out  so  fair  and  wide  an  extent  of  fertile  soil 
as  that  of  Santa  Clara;  but,  on  the  other  hand,  there  are  more  ranges 
of  low  and  rolling  hills  adapted  for  cultivation,  and,  with  the  charming 
though  narrow  valleys  between  them,  enabling  the  counties  enume- 


NORTH  OF  THE  BAY  OF  SAN  FRANCISCO. 


81 


rated  above  to  vie  with  any  portion  of  the  State  of  equal  area  in  fer¬ 
tility.  For  picturesque  beauty  and  general  salubrity  of  climate,  it 
would  not  be  easy  to  decide  which  of  the  valleys  leading  out  from  the 
Bay  of  San  Francisco  is  entitled  to  pre-eminence;  taken  together,  they 
may  well  claim  to  be  considered  as  one  of  the  most  attractive  portions 
of  our  country. 

The  whole  of  Marin  County  is  thrown  up  into  rolling  hills  of  moder¬ 
ate  height,  and  the  depressions  between  them  have  little  level  ground ; 
nor  is  there  much  regularity  in  the  distribution  of  the  ridges,  a  circum¬ 
stance  which  is  due  to  the  irregular  dip  and  strike  of  the  strata,  and 
the  still  more  irregular  manner  in  which  they  have  undergone  a  more 
or  less  complete  alteration  by  chemical  agencies  since  their  deposition. 
In  general  character  the  rocks  of  this  countv  are  similar  to  those  de- 
scribed  as  occurring  on  the  peninsula  south  of  San  Francisco ;  of  these 
they  are  in  reality  the  continuation,  although  apparently  separated 
from  them  by  the  Golden  Gate. 

The  culminating  point  of  the  county  is  Tamalpais,*  which  rises  to 
the  height  of  2597  feet,  forming  a  portion  of  a  ridge  which  extends 
across  the  peninsula  in  a  nearly  east  and  west  direction ;  in  this  ridge 
there  are  three  summits  of  nearly  equal  height,  all  being  over  2550  feet. 
One  of  these  points  is  a  Coast  Survey  station,  and  is  called  “  Table 
Mountain.”  These  are  all  of  hard,  metamorphic  sandstone,  not  so 
much  altered,  however,  as  to  obliterate  the  granulation  or  the  lines  of 
stratification.  Near  the  eastern  summit,  veins  of  quartz  occur,  portions 
of  which  are  distinctly  banded,  as  if  deposited  from  water.  Some  of 
these  are  said  to  contain  gold,  and  they  have  been  worked  but  found 
too  poor  to  pay  for  the  labor.  Tbe  summit  lias  been,  and  is  perhaps 
now,  held  as  a  quartz  claim.  The  eastern  summit  is  very  sharp,  the 
slope,  as  seen  in  the  sky-outline  from  San  Rafael,  being  25°  on  both 

*  Tamalpais  is  the  name  by  which  this  mountain  is  now  universally  known  in  San 
Francisco,  from  which  it  is  so  conspicuous  and  beautiful  an  object.  It  was  called  “Mount 
Palermo”  by  the  United  States  Exploring  Expedition,  and  “  Table  Mountain”  by  Beechv 
and  the  United  States  Coast  Survey.  The  Coast  Survey  station  is  not,  however,  on  the 
highest  point,  but  is  about  a  mile  to  the  west  of  it.  The  elevation  of  the  station  is  given 
at  2597  feet ;  that  of  Tamalpais  itself  at  2604  feet.  The  name  is  said  to  have  originated 
in  the  fact  that  this  region  was  formerly  the  residence  of  the  Tamal  Indians;  see  David¬ 
son’s  Directory  of  the  Pacific  Coast,  in  Coast  Survey  Report  for  1862. 

GK0L.  VOL.  T.  — 11 


82 


GEOLOGY  OF  THE  COAST  RANGES 


sides,  and  the  whole  mountain  is  deeply  furrowed  by  denudation. 
About  three-fourths  of  a  mile  west  from  the  highest  point,  serpentine 
occurs  in  large  quantities,  as  also  on  the  northern  slope.  On  the  north¬ 
western  side  there  are  immense  masses  of  this  rock,  forming  the  ridge 
between  the  Tomales  y  Baulines,  San  Geronimo,  and  Canada  de  Her¬ 
rera  Ranches,  and  rising  to  the  altitude  of  1829  feet.  This  belt,  which 
is  almost  entirely  of  serpentine,  extends  several  miles  to  the  north¬ 
west.  On  the  north  slope  of  Tamalpais  altered  slates  occur,  at  the  alti¬ 
tude  of  about  1200  feet,  and  have  a  northwest  strike  and  a  very  high 


hut  irregular  dip  to  the  southwest. 

Between  Petaluma  and  San  Rafael  on  the  east  and  Tomales  Bay  on 
the  west,  the  rock  is  entirely  metamorphic  or  eruptive,  with  the  excep¬ 
tion  of  very  limited  deposits  of  unaltered  Tertiary  along  the  northern 
part.  The  whole  region  is  broken  up  into  ridges,  of  which  the  higher 
ones  are  generally  of  metamorphic  sandstone,  usually  very  much  altered, 
but  not  always  so.  There  are  also  slates  and  shales  in  various  stages 
of  alteration,  sometimes  assuming  the  form  of  the  jaspery  rock  so  cha¬ 
racteristic  of  the  summit  of  Monte  Diablo;  some  mica-slate  was'  also 
noticed,  although  it  does  not  occur  in  large  quantity. 

Eruptive  rock  occurs  in  various  places.  About  one  and  a  half  miles 
west  of  San  Rafael,  at  Sugar  Loaf  Hill,  there  is  a  mass  of  trachyte  of 
a  light  brown ishrgray  color,  which  extends  for  a  short  distance  east  and 
west.  Rear  Rudesill’s  Landing  a  very  hard,  compact,  and  fine-grained 
basalt  occurs  and  is  seen  in  several  hills.  It  forms  a  belt  or  dyke, 
extending  about  north-rnorthwest,  and  is  well  exposed  about  three- 
fourths  of  a  mile  southwest  of  Petaluma,  where  it  is  about  two  hundred 
yards  wide.  It  has  here  a  columnar  structure,  the  columns  being  very 
regular,  usually  six-sided,  and  about  two  feet  in  diameter,  although 
sometimes  as  much  as  three.  The  joints  or  columns  are  from  one  to 
three  feet  long,  and  generally  dip  to  the  south  at  an  angle  of  from  60° 
to  80°,  although  occasionally  vertical.  This  rock  is  quarried  for  build¬ 
ing,  for  which  purpose  it  is  well  adapted,  breaking  equally  well  in  all 
directions,  and  rough -dressing  easily;  of  course  it  is  extremely  durable. 
At  the  quarry  the  dyke  has  a  direction  of  K.  65°  W.  Eruptive  rock 
was  also  seen  in  the  high  hills  on  the  Olampoli  and  Santa  Margarita 
Ranches,  hut  was  not  exposed  so  that  it  could  be  well  examined. 


NORTH  OF  THE  BAY  OF  SAN  FRANCISCO.  83 

Among  .the  varieties  of  metamorphic  rock  in  this  region,  silicions 
and  jaspery  masses  are  predominant.  In  a  hill  about  a  mile  north  of 
San  Rafael,  there  is  an  immense  outcrop  of  quartz,  approaching  flint 
in  appearance ;  it  is  mostly  of  a  light-green  color,  although  portions 
are  white,  gray,  and  black.  It  has  a  conclioidal  fracture,  and  a  ten¬ 
dency  to  separate  into  prismatic  and  cubical  fragments,  with  which  the 
whole  surface  of  the  hill  is  covered. 

The  hills  of  the  peninsula  three  miles  northeast  of  San  Rafael  have 
been  the  scene  of  considerable  gold  excitement.  They  are  made  up 
of  metamorphic  sandstone,  including  veins  of  quartz,  some  of  which 
probably  do  contain  a  little  of  the  precious  metal,  but  they  are  not 
regular  enough  to  pay  for  working.  There  are  some  slates  in  this 
vicinity,  with  a  northeasterly  dip. 

In  crossing  the  peninsula  from  San  Rafael  to  the  head  of  Tomales 
Bay,  metamorphic  rocks  were  everywhere  met  with,  the  only  exception 
being  the  small  outcrop  of  trachyte  before  noticed.  These  rocks  seemed 
to  be  of  Cretaceous  age,  and  at  seven  miles  from  San  Rafael  shales 
occur,  scarcely  altered  at  all,  and  precisely  similar  in  character  to  the 
shales  of  that  age  near  Monte  DiablOi  In  close  proximity  to  these  un¬ 
altered  strata,  and  in  the  same  direction,  masses  of  jasper  were  observed, 
evidently  the  result  of  the  metamorpliism  of  the  shales,  and  this  jas¬ 
pery  rock  occurs  at  intervals  along  the  whole  line  explored  across  the 
peninsula.  Metamorphic  sandstones  also  occur  in  abundance,  contain¬ 
ing  epidote;  other  forms  of  altered  Cretaceous  rocks,  which  liav.e  al¬ 
ready  been  noticed  as  observed  near  Monte  Diablo,  also  occur  here. 
Serpentine  appears  in  considerable  quantity,  and  the  peculiar  silicious 
rock,  which  is  usually  associated  with  cinnabar,  is  found  about  nine 
miles  from  San  Rafaeh 

Between  Petaluma  and  the  entrance  of  Tomales  Bay,  the  hills  are 
much  lower,  quite  a  well-marked  depression  extending  across  the  pe¬ 
ninsula.  The  rock  exposed  on  this  line  is  mostly  metamorphic,  the 
strata  highly  altered  and  much  contorted  and  broken.  In  various 
places  patches  of  Tertiary  sandstone  rest  unconformably  upon  these 
altered  strata.  These  are  best  seen  at  Estero  San  Antonio,  about  three 
miles  north  of  Tomales,  where  a  section  two  hundred  and  fifty  or  three 
hundred  feet  thick  may  be  studied.  The  rocks  here  are  soft,  yellow 


84 


GEOLOGY  OF  THE  COAST  RANGES 


sandstones,  with  lar<>e  nodules  of  hard  blue  calcareous  sandstone  im- 
bedded  in  them.  These  beds  are  quite  fossiliferous,  and  appear  to 
belong  to  the  Miocene  division  of  the  Tertiary. 

Patches  of  these  sandstones,  in  all  cases  nearly  horizontal,  occur  at 
various  points  between  Tomales  and  Petaluma,  and  several  of  these 
were  seen  ‘near  the  first-named  place,  especially  two  miles  west  of  it, 
where  they  form  large  outcrops.  The  metamorphie  rocks  had  suffered 
extensive  denudation  before  the  deposition  of  these  Tertiary  strata, 
which  have  themselves  been  extensively  denuded  since  their  formation, 
but  not  otherwise  disturbed. 

West  of  Tomales  Bay  lies  a  series  of  ridges  having  a  direction  of 
about  N.  36°  W.,  and  extending  from  Tomales  Point  to  Baulines  Bay, 
a  distance  of  about  twenty-eight  and  a  half  miles.  The  principal  ridge 
is  on  the  western  side,  and  is  separated  from  the  ridges  east  by  a  nearly 
straight  valley,  the  northern  portion  of  which,  for  about  fifteen  miles, 
is  occupied  by  Tomales  Bay,  the  remainder  by  the  swamps  at  the  head 
of  the  bay  and  the  valley  of  the  Arroyo  Olemus  Loke,  terminating  on 
the  south  in  Baulines  Bay,  thus  forming  a  well-marked  and  continuous 
depression  through  the  entire  distance. 

The  extremity  of  Tomales  Point  is  entirely  of  granite,  mostly  soft  and 
decomposed.  About  three  and  a  half  miles  from  the  Point,  at  White’s 
Gulch,  sandstone  occurs,  resting  on  this  granite  nearly  horizontally,  or 
with  a  slight  northeastern  dip.  On  these  sandstones  rest  white,  argil¬ 
laceous  slates,  in  places  somewhat  silicified,  and  resembling  the  bitumi¬ 
nous  and  infusorial  strata  at  Santa  Cruz  and  Monterey.  Farther  south, 
near  Abbott’s  Banch  House,  the  sandstone  occurs  in  large  masses,  hav¬ 
ing  a  low  dip  to  the  southwest,  from  5°  to  8°,  usually.  Xo  fossils 
were  found  in  these ;  but  they  appear  to  be  of  the  same  age  as  the 
sandstones  found  at  Estero  San  Antonio,  near  Tomales.  Between  the 

A 

highest  points  near  the* head  of  Tomales  Bay  and  Punta  Reyes,  there 
are  some  minor  ridges  made  up  entirely  of  sandstone,  having  a  low 
southwest  dip ;  these  are  probably  all  Miocene.  The  granite  rises  in 
high  ridges  near  the  head  of  the  bay,  and  in  places  is  accompanied  by 
mica-slate,  which  latter  rock  is  too  much  broken  for  any  satisfactory 
idea  to  be  obtained  of  its  position.  Metamorphie  limestone  also  occurs 
associated  with  these  rocks;  it  undoubtedly  runs  through  in  nearly  a 


NORTH  OF  THE  BAY  OF  SAN  FRANCISCO. 


85 


straight  line  to  Tomales  Bay,  and  lias  been  burned  quite  extensively 
for  lime  at  several  places.  It  is  too  much  metamorphosed  to  show  well- 
marked  lines  of  stratification,  being  quite  crystalline,  and  containing 
thin  plates  of  graphite.  It  appears  to  be  the  continuation  of  the  lime¬ 
stone  belt  of  Santa  Cruz  and  San  Andreas,  in  San  Mateo  County. 

Punta  de  los  Reyes  is  of  granite,  rising  in  a  high  promontory,  hut  it 
is  separated  from  the  ridge  of  Tomales  Point  by  a  deep  depression, 
which  is  partly  occupied  by  Tertiary  sandstones.  Granite  also  occurs 
at  Bodega  Head,  probably  a  continuation  of  the  mass  of  Tomales  Point. 

Napa  Valley  extends  north  from  Napa  City,  about  twenty-five  miles, 
to  the  base  of  Mount  St.  Helena.  From  the  village  of  that  name  to 
the  head  of  the  valley  is  about  twelve  miles,  and  in  this  portion  it  is 
about  a  mile  wide.  It  is  one  of  the  most  beautiful  and  fertile  valleys 
of  the  State.  High  ridges  of  metamorphic  rock  enclose  it  on  both 
sides,  and  in  the  central  portion,  especially  near  Sebastopol,  or  Yount’s, 
a  number  of  low  isolated  hills  of  the  same  formation  rise  from  the 
bottom ;  otherwise,  it  is  a  nearly  level  tract,  with  a  gently  descending 
slope  from  its  head  to  the  marshy  region  at  the  head  of  San  Pablo 
Bay.  The  upper  part  of  the  valley  has  many  trees,  among  which  are 
several  species  of  oaks,  pine,  spruce,  madrona,  and  an  occasional  red¬ 
wood.  The  following  are  the  altitudes,  above  tide-water,  of  some  of 
the  points  in  this  valley. 

Near  Yount’s  Mill,  Camp  64,  ....  102  feet. 

St.  Helena  Village,  “  67,  .....  215  “ 

Fowler’s,  “  65,  .....  369  11 

Summit  of  pass  between  Napa  and  Knight’s  Valleys,  .  749  “ 

At  the  head  of  the  valley,  the  western  ridge  becomes  quite  depressed 
and  connects  with  the  St.  Helena  Mountain  by  a  low  divide,  from  which 
we  descend  to  the  northwest  into  Knight’s  Valley,  which  is  drained 
into  Russian  River  Valley.  All  through  this  region  the  small  side- 
valleys  on  the  numerous  creeks  are  most  charmingly  situated,  few  por¬ 
tions  of  the  State  being  able  to  show  more  attractive  and  valuable 
farms  and  ranches. 

A  high,  sharp  ridge  on  the  west  of  Napa  Valley,  between  Sebastopol 
and  St.  Helena,  was  ascended;  our  time  not  permitting  us  to  make 


86 


GEOLOGY  OF  THE  COAST  RANGES 


anything  more  than  a  very  general  examination  of  this  region.  This 
ridge  is  covered,  near  its  summit,  with  low  chaparral,  and  is  a  very 
conspicuous  point  in  passing  up  the  valley.  The  rock  of  which  it  is 
chiefly  made  up  is  a  metamorphic  sandstone,  having  a  strike  of  about 
N.  50°  W.  A  few  outcrops  of  serpentine  were  seen  in  the  hills  to  the 
west.  The  summit  commanded  a  fine  view  of  Napa  Valley  and  the 
ridges  to  the  east  of  it,  as  well  as  of  the  broken  region  to  the  north¬ 
west,  between  Napa  and  Russian  River  Valleys.  All  this  portion  to  the 
west  seems  to  be  made  up  of  metamorphic  sandstones,  the  volcanic 
rocks  of  the  eastern  side  not  crossing  over  to  this.  The  point  ascended 
being1  without  a  name  was  called  Mount  Henry,  in  honor  of  the  dis- 
tinguished  secretary  of  the  Smithsonian  Institution.  Its  height  was 
found  to  be  2398  feet  above  the  sea,  and  the  highest  points  of  the  ridge 
were  estimated  at  2600  feet.  A  ridge  to  the  northwest,  connected  with 
Mount  Henry  by  a  low  divide  of  1600  to  1800  feet  in  elevation,  was 
found  to  be  about  150  feet  higher  than  the  one  ascended.  Another 
ridge  to  the  south-southeast  was  also  somewhat  higher,  and  is  conspicu¬ 
ous  for  a  great  distance,  on  account  of  a  few  scattered  pines  upon  its 
summit.  These  ridges  have  a  general  northwest  and  southeast  direc- 
tion,  but  there  are  no  continuous  and  well-defined  valleys  between 
them  like  that  of  Napa. 

Mount  St.  Helena  is  the  culminating  point  of  the  ridges  between  the 
Bay  of  San  Francisco  and  Clear  Lake,  and  is,  with  the  exception  of 
Mount  Hamilton,  the  highest  mountain  between  San  Carlos  and  the 
high  region  west  of  Colusi  County,  where  are  many  points  which  have 
not  yet  been  measured  and  of  which  little  or  nothing  is  known.  The 
height  of  Mount  St.  Helena  is  given  by  the  Coast  Survey  at  4343  feet, 
or  about  one  hundred  feet  less  than  that  of  Mount  Hamilton.  It  was 
ascended  by  Wosnessensky,  a  Russian  naturalist,  in  1841,  and  named  in 
honor  of  the  Empress  of  Russia,  and  a  copper  plate,  with  an  inscrip¬ 
tion,  was  fastened  on  the  summit,  which  was  afterwards  removed  by 
thoughtless  or  malicious  persons,  and  is  now  preserved  in  the  Museum 
of  the  Geological  Survey.*  This  mountain,  from  which  the  volcanic 


*  Wosnessensky,  a  naturalist  attached  to  the  Zoological  Museum  of  St.  Petersburg, 
was  sent  out  to  the  Pacific  by  the  Academy  of  Sciences  in  1839,  and  spent  ten  years  in 
travelling  through  the  countries  bordering  its  northern  shores,  from  California  to  Kam- 


NORTH  OF  THE  BAY  OF  SAN  FRANCISCO. 


87 


materials  spread  over  the  country  to  the  east  and  southeast  appear  to 
have  originated,  is  a  part  of  the  volcanic  belt  which  extends  from  near 
Napa  through  to  Clear  Lake  at  least,  and  how  much  farther  is  not  yet 
known.  It  is  a  grand  object  with  its  steep  and  rocky  sides,  although 
it  does  not  tower  above  the  surrounding  ridges  to  a  sufficient  height  to 
make  it  very  prominent  at  a  distance.  As  seen  from  Napa,  it  has  a 
fiat,  table-like  summit.  Mr.  Hoffman  ascended  to  within  three  hun¬ 
dred  feet  of  the  top,  and  saw  nothing  but  volcanic  rocks  on  the  side  on 
which  he  climbed. 

It  is  not  certainly  known  that  this  volcanic  range  extends  through 
uninterruptedly  to  Clear  Lake;  but  rocks  of  this  class,  including  tra¬ 
chytes,  basaltic  lava,  obsidian,  and  pumice,  which  extend  along  the 
southwestern  side  of  Clear  Lake,  are  in  a  line  with  the  volcanic  belt  on 
the  east  of  Napa.  The  existence  of  hot  springs  in  the  valley,  at  sev¬ 
eral  points,  is  connected  with  this  volcanic  range.  The  “  Hot,  Springs” 
seven  miles  southeast  of  the  summit  of  Mount  St.  Helena,  in  a  side- 
valley  running  out  from  Napa  Valley  to  the  northeast,  have  quite  a 
reputation  for  their  curative  qualities.  The  waters  had  a  temperature 
(November,  1861)  of  from  157°  to  168°,  and  they  issue  copiously  around 
the  base  of  a  low  conical  hill  of  metamorphic  sandstone.  The  “  Napa 
Springs,”  or  the  “  Sulphur  Springs,”  in  a  side-canon  two  miles  southwest 
of  St.  Helena,  are  much  resorted  to  by  patients  and  pleasure-seekers. 

Another  fact,  connected  with  the  volcanic  character  of  the  rocks  of 
Mount  St.  Helena,  was  testified  to  by  a  number  of  independent  and 
reliable  witnesses  at  different  places  in  this  vicinity.  This  is,  that  in 
December,  1859,  a  tremendous  explosion  was  heard  in  the  mountain, 
like  the  discharge  of  heavy  artillery,  causing  a  distinct  vibration  of  the 
ground  like  an  earthquake,  except  that  the  cause  seemed  to  be  local 
and  was  referred  by  all  to  the  mountain  itself,  where  the  noise  seemed 
to  originate  and  from  which  in  all  directions,  for  many  miles,  it  was  dis¬ 
tinctly  heard.  It  is  not  unlikely  that  it  may  have  been  caused  by  the 
falling  of  heavy  masses  of  rock  in  some  of  the  subterranean  cavities 
which  we  know  to  exist  in  these  volcanic  regions. 

schatka.  The  plate  bears  his  name  and  that  of  a  companion  (Tsehernich),  with  the  date 
of  their  ascent  (June  12,  1841),  and  the  word  “  Russians”  twice  repeated,  once  in  their 
native  tongue  and  again  in  Latin.  It  was  presented  to  the  Survey  by  Dr.  J.  A.iVeatch, 


88 


GEOLOGY  OF  THE  COAST  RANGES 


A  hasty  exploration  was  made  of  the  region  to  the  northwest  of 
Mount  St.  Helena,  as  far  as  the  Geysers,  and  including  most  of  the  lo¬ 
calities  where,  in  1861,  quicksilver-mines  were  being  opened  or  pros¬ 
pected  for;  but  our  work  in  the  field  was  put  a  stop  to  just  as  we 
arrived  at  the  Geysers,  by  the  setting  in  of  the  severe  winter  storms  of 
1861-2.  Afterwards,  in  1863,  a  few  days  were  devoted  to  an  examina¬ 
tion  of  the  region  around  the  southern  end  of  Clear  Lake,  during 
which  we  passed  up  the  Napa  Valley  as  far  as  St.  Helena,  and  then 
crossed  the  range  and  went  north  by  the  Locoallomi  Ranch  and  Pope 
Valley,  and  returned  from  the  lake  by  way  of  Bereyessa  Valley  to 
Suscol. 

The  country  to  the  north  of  Knight’s  Valley  and  McDonald’s  is  a 
rough  and  mountainous  one,  and  no  map  of  any  portion  of  it  has  yet 
been  made.  The  ridges,  as  well  as  the  rocks,  are  very  much  broken, 
and  the  country  in  general  elevated  and  abounding  in  picturesque 
scenes;  with  its  great  facility  of  access  from  San  Francisco  and  the 
attractions  of  the  Geysers,  it  cannot  fail  to  become,  in  time,  a  place 
much  resorted  to  by  tourists. 

In  the  vicinity  of  McDonald’s  no  other  rock  was  seen  than  metamor- 
phic  sandstone,  in  various  stages  of  alteration ;  where  most  changed,  it 
passed  into  mica-slate  and  contained  large  masses  of  actinolite,  like 
those  found  near  San  Pablo.  To  the  north  of  McDonald’s  rises  the 
high  ridge  known  as  Pine  Mountain,  having  an  elevation  of  from  3200 
to  3500  feet.  This  was  crossed  in  two  places,  and  found  to  be  made 
up  of  metamorphic  rocks  resembling  those  seen,  farther  south  and 
known  to  be  of  Cretaceous  age.  Some  mica-slate  was  observed,  with 
much  serpentine  and  large  bodies  of  granular,  quartzose  metamorphic 
sandstone.  The  summit  of  this  ridge  is  magnificently  wooded  with 
pitch  pine,  sugar  pine,  Douglas  spruce,  and,  on  the  northwest  slope, 
the  nutmeg  tree  ( Torreya) ;  the  sugar  pine  was  only  seen  on  the  higher 
ridges. 

A  few  miles  northwest  of  Pine  Mountain  rises  a  still  higher  ridge, 
pine-clad  on  its  summit,  and  known  as  Mount  Cobb;  this  was  not  vis¬ 
ited,  but  was  estimated  at  about  3800  feet  in  height.  The  ridges  which 
intervene  between  these  are  from  2800  to  3000  feet  high.  This  region 
is  made  up  of  highly  metamorphic  rocks,  including  serpentine  in  im- 


NORTH  OF  THE  BAY  OF  SAN  FRANCISCO. 


89 


mense  quantities  and  other  rocks  similar  in  association  and  in  litholog¬ 
ical  character  to  the  mercury-hearing  rocks  of  New  Almaden  and  New 
Idria;  in  fact  the  resemblance  is  quite  complete,  and  extends  to  the 
associated  minerals,  a  large  number  of  deposits  of  cinnabar  having 
been  discovered  here,  although  none  have  yet  proved  sufficiently  ex¬ 
tensive  to  be  worked  continuously  with  profit. 

The  locality  of  these  mines  and  explorations,  which  were  most  ac¬ 
tively  pursued  in  1861,  is  in  the  serpentine  belt  noticed  above  as  occur¬ 
ring  between  Pine  Mountain  and  Mount  Cobb,  a  single  claim  only  (the 
“  Pine  Hill”)  lying  south  of  the  crest  of  Pine  Mountain.  This  quick¬ 
silver  belt,  as  it  is  called,  extends  in  a  general  northwest  and  southeast 
direction,  and  about  33,000  feet  of  claims  had  been  taken  up  on  it  in 
1861.  The  peculiar  quicksilver  rock  occurs  at  intervals  along  this  belt, 
and  there  is  no  doubt  that  the  number  of  points  where  cinnabar  may 
be  found  is  very  great,  and  it  is  not  at  all  unlikely  that  some  large  de¬ 
posit  of  this  ore  may  be  struck  eventually.  The  following  claims  were 
examined:  “Cincinnati,”  “Dead  Broke,”  “Pittsburg,”  “Pioneer,” 
and  “Denver;”  these  being  the  only  ones  where  any  work  of  conse¬ 
quence  had  been  done  at  the  time  of  our  visit. 

The  “  Cincinnati”  is  on  the  hill-side  near  a  steep  canon,  northeast 

# 

of  Pine  Mountain ;  from  it  Mount  St.  Helena  bears  S.  32°  E.,  and  the 
mine  was  estimated  to  have  an  altitude  of  about  2500  feet.  The  pre¬ 
vailing  rock  is  serpentine  filled  with  threads  and  veinlets  of  quartz, 
running  through  it  in  every  direction,  presenting  rather  a  peculiar  ap¬ 
pearance,  as  some  of  the  quartz  is  in  a  crystallized  form.  Both  cinna¬ 
bar  and  native  mercury  have  been  found  here ;  but  there  was  little  ap¬ 
pearance  of  regularity  in  the  deposit,  and  no  large  mass  of  ore  had 
been  discovered,  although  a  drift  had  been  run  in  two  hundred  feet  or 
more  “  to  strike  the  lead.” 

The  “  Dead  Broke”  lies  about  a  mile  west  of  the  Cincinnati.  The 
rock  here  consists  of  alternating  layers  of  a  dark  and  light-colored  and 
partly  decomposed  quartzite ;  the  strike  of  these  is  about  N.  5°  W. — 
S.  5°  E.,  and  their  dip,  which  is  to  the  west,  about  45°.  On  the  east 
side  of  the  ridge  imperfect  serpentine  was  seen,  and  a  level  had  been 
driven  in  it  for  265  feet.  The  cinnabar,  of  which  rich  specimens  had 

G EOL.  VOL.  I. — 12 


90 


GEOLOGY  OF  THE  COAST  RANGES 


been  procured,  was  contained  in  a  stratum  about  four  inches  wide  and 
parallel  with  the  formation. 

The  “  Pittsburg”  Claim  is  one-half  a  mile  N.  15°  W.  from  the  Dead 

© 

Broke,  and  some  cinnabar  has  been  found  here  in  serpentine  ;  but  no¬ 
thing  regular  or  permanently  valuable. 

From  this  last-mentioned  claim  several  ridges  were  crossed,  which 
were  estimated  at  about  3000  feet  above  the  sea-level,  in  going  towards 
the  Pioneer  Claim,  which  is  about  four  miles  from  the  one  last-men¬ 
tioned,  in  a  northwesterly  direction.  A  great  variety  of  metamorphic 
rocks  were  passed  over  on  this  line,  consisting  of  sandstones  in  every 
stage  of  metamorphism,  and  serpentine,  with  its  varieties  marmolite 
and  chrysolite,  and  quartz  veins  ramifying  through  it.  The  serpentine, 
however,  is  the  predominating  rock. 

The  “  Pioneer”  Claim  is  the  one  on  which  the  most  mining  had  been 
done  at  the  time  of  our  visit  to  this  region.  Work  was  commenced 
here  in  June,  1861.  The  rock  most  nearly  associated  with  the  ore  is 
the  same  peculiar  silicious  variety  usually  seen  at  the  cinnabar-mines 
of  California,  and  it  is  enclosed,  on  both  sides,  by  serpentine.  The 
strike  of  the  metalliferous  lode  or  vein  was  nearly  northwest  and  south¬ 
east,  and  the  dip  46°  to  the  southwest.  The  metal  exists  here  both  in 
the  form  of  the  sulpliuret,  as  cinnabar,  and  in  the  native  state ;  indeed, 
so  far  as  we  know,  it  is  one  of  the  most  remarkable  localities  of  native 
mercury  ever  discovered.  The  metal  occurs  disseminated  in  fine  glob¬ 
ules  through  the  veinstone,  or  in  larger  quantities  in  the  interior  of 
quartz  geodes  or  “  pockets.”  Over  six  pounds  have  been  saved  from 
a  single  pocket,  and  one  of  the  first  cavities  broken  into  yielded  four 
pounds  three  ounces  of  the  metal,  besides  what  was  unavoidably  lost  in 
collecting;  these  facts  are  stated  on  the  authority  of  Mr.  B.  C.  Wattles, 
the  superintendent.  Large  masses  of  rock,  with  the  mercury  exuding 
from  them  and  standing  in  drops  all  over  the  surface,  especially  of  a 
fresh  fracture,  were  obtained  for  the  State  collection.  Considerable 
bituminous  matter  occurs  here,  as  in  most  of  the  other  mercury-mines 
of  the  State,  and  some  of  the  quartz  geodes  contain  bitumen. 

A  furnace  was  erected  here,  in  a  canon  to  the  northeast  of  the  mine, 
and  some  attempts  made  to  extract  the  metal  from  the  ore,  but  these 
had  not  been  pecuniarily  successful  at  the  time  of  our  visit,  and  it  is 


NORTH  OF  TIIE  BAY  OF  SAN  FRANCISCO. 


91 


believed  that  the  mine  is  now  abandoned,  quite  a  large  sum  of  money, 
probably  not  less  than  $40,000,  having  been  expended  here. 

On  the  south  slope  of  the  same  ridge  in  which  the  Pioneer  Claim  is 
situated,  and  in  a  southeast  direction  from  it,  is  the  Denver  Claim,  which 
consisted  of  a  drift  run  in  over  two  hundred  feet  through  serpentine, 
without  a  trace  of  mercury  or  cinnabar,  so  far  as  could  be  perceived. 
Some  interesting  specimens  of  hydromagnesite  were  obtained  here,  in 
fibrous,  stellated  forms. 

For  convenience,  reference  will  be  made  here  to  the  other  localities 
Avhere  quicksilver  ores  have  been  mined,  north  of  the  Bay  of  San  Fran¬ 
cisco;  although  they  are  not  in  the  immediate  vicinity  of  those  which 
have  just  been  noticed. 

One  locality  of  considerable  importance  is  in  Pope  Valley,  three  or 
four  miles  northeast  of  Mount  St.  Helena.  The  rock  here  shows  all 
the  characteristics  of  the  quicksilver-bearing  rock  of  the  other  districts 
where  this  metal  occurs.  The  same  variety  of  half-formed  serpentine, 
or  sandstone  in  process  of  metamorphism,  of  a  dark-brown  color,  of 
which  a  large  mass  occurs  a  little  west  of  the  summit  of  Monte  Diablo, 
is  seen  here.  There  appears  to  be  a  considerable  quantity  of  cinnabar 
disseminated  through  the  rock,  but,  as  in  many  other  localities  of  this 
mineral,  it  is  extremely  irregular  in  its  mode  of  occurrence,  so  that  the 
workings  cannot  be  considered  as  having  been  successful  (up  to  the 
year  1863),  as  they  have  failed  to  develop  any  large  body  of  ore. 

A  company  called  the  “Hamilton  Quicksilver  Mining  Company” 
put  up  six  retorts  near  this,  and  smelted  the  ore,  paying  a  royalty  of 
seven  cents  for  every  pound  of  quicksilver  obtained.  This  concern 
had  suspended  operations  in  the  autumn  of  1863,  after  having  pro¬ 
duced,  as  near  as  could  be  ascertained,  about  17,000  pounds  of  the 
metal.  The  locality  of  the  furnace  is  on  the  stage  road  (as  it  was  in 
1863)  from  St.  Helena  to  Clear  Lake ;  the  mine  was  about  a  mile  to 
the  west  of  it,  and  explorations  were  still  making  here  at  that  time  by 
Mr.  Billings,  the  proprietor,  in  the  hope  of  striking  a  more  concen¬ 
trated  body  of  the  ore. 

About  eighteen  miles  from  Lower  Lake,  a  small  settlement  near  the 
southern  end  of  Clear  Lake,  on  the  road  to  Suisun,  is  a  locality  where 
mining  for  quicksilver  was  carried  on  in  1863.  This  is  called  the 


92 


GEOLOGY  OF  THE  COAST  RANGES 


“Lake  Mine;”  and  about  two  miles  farther  down  the  valley  is  another, 
the  “  Excelsior  Mine.”  At  the  Lake  Mine  the  rocks  are  slightly  altered, 
impure  calcareo-argillaceous  shales.  The  ore,  which  has  not  yet  been 
proved  to  exist  here  in  large  quantity,  is  quite  distinct  from  any  seen 
elsewhere  in  the  State,  on  account  of  its  being  associated  with  the  sul- 
phuret  of  antimony,  which  occurs  in  needle-shaped  crystals  and  crys¬ 
talline-granular  masses.  It  appears  to  form  lenticular  bodies  in  the 
shales,  and  was  not  observed  to  be  associated  with  the  usual  silicious 
rock  seen  in  other  localities  where  cinnabar  is  found.  The  rocks  in 
this  vicinity  have  all  the  appearance  of  belonging  to  the  Cretaceous 
series,  and  immense  masses  of  serpentine  occur  a  little  to  the  north  and 
extend  for  a  long  distance  in  that  direction.  The  Excelsior  Mine  has 
been  worked  to  a  considerable  extent,  the  ore  here  being  a  good  deal 
mixed  with  iron  pyrites ;  reduction  works  have  been  in  operation  here, 
and  were  yielding  a  little  quicksilver  in  September,  1863;  the  amount 
produced  was  not  ascertained,  nor  are  we  informed  whether  the  fur¬ 
naces  are  still  in  operation. 

The  trouble  with  all  the  deposits  of  cinnabar  just  noticed  is,  that 
they  are  too  irregular,  and  that  the  ore  is  not  sufficiently  concentrated, 
or  in  large  enough  masses.  There  is  no  reason  why  heavy  deposits  of 
valuable  ore  should  not  be  met  with,  in  sinking  upon  the  outcrops  in 
which  small  quantities  of  it  are  exhibited ;  but  it  is  far  from  being  a 
matter  of  certainty ;  and,  as  the  result  of  actual  experience,  it  may  be 
stated,  that  in  the  only  instance  where  a  deposit  of  ore  has  been  discov- 
ered  sufficiently  large  to  pay  for  continuous  working,  there  was  a  cor¬ 
respondingly  large  display  at  the  Surface ;  this  was  at  the  Hew  Almaden 
Mine,  which  was  undoubtedly  known  to  the  natives  for  a  long  time 
previous  to  the  arrival  of  the  whites  on  these  shores. 

Very  peculiar  and  interesting  specimens  of  cinnabar  were  shown  us 
at  Clear  Lake,  the  localitv  of  which  we  were  unable  to  visit.  These 
consisted  of  rounded  and  water-worn  masses  of  pure  cinnabar,  with 
specks  of  native  gold  enclosed  in  them,  which  were  said  to  have  come 
from  near  Sulphur  Springs,  four  miles  south  of  Bear  Valley,  on  the 
trail  from  Clear  Lake  to  Colusi.  Considerable  quantities  of  this  re¬ 
markable  combination  of  ore  and  metal  are  said  to  have  been  washed 
out  from  the  bed  of  a  creek  in  the  canon  at  that  place. 


NORTH  OF  THE  BAY  OF  SAN  FRANCISCO. 


93 


The  hot  springs,  known  as  the  Geysers,  are  situated  about  half  way 
between  Healdsburg  and  the  southern  end  of  Clear  Lake,  and  are  ap¬ 
proached  by  a  road  from  Ray’s  Ranch,  or  by  a  trail  from  McDonald’s, 
the  route  being  in  either  case  extremely  picturesque,  the  excursion  from 
San  Francisco  to  the  Geysers  forming  one  of  the  pleasantest  and  most 
attractive  ones  that  can  be  made  from  the  city  with  small  expenditure 
of  time.  We  visited  the  locality  in  question  from  the  Pioneer  Mine, 
and,  the  winter  rains  having  already  set  in,  were  only  able  to  make  a 
hasty  examination  of  the  place  and  no  topographical  survey,  so  that 
our  notice  of  it  can  only  be  of  the  briefest  kind. 

On  our  way  to  the  Geysers  we  passed  along  the  high  ridge  that  con¬ 
nects  Sulphur  Peak,  or  Geyser  Peak  as  it  is  also  called,  with  Pine 
Mountain.  It  is  probably  about  3000  feet  high  and  commands  a  most 
extensive  view  both  to  the  north  and  the  south.  The  rocks  are  all 
metamorphic  Cretaceous,  with  very  heavy  beds  of  serpentine,  similar 
to  the  other  ridges  in  this  region.  Sulphur  Peak  is  one  of  the  stations 
of  the  primary  triangulation  of  the  Coast  Survey,  and  is  given  in  their 
report  as  3471  feet  high ;  it  is  said  to  be  the  finest  point  of  view  in  this 
part  of  the  State,  commanding  a  large  part  of  the  Russian  River  Valley, 
and  of  the  wild  mountainous  region  to  the  northwest  between  the  Gey¬ 
sers  and  Clear  Lake. 

There  are  two  localities  of  hot  springs  in  this  vicinity,  one  known  as 
the  Geysers,  the  other  as  the  Little  Geysers,  although  it  must  be  al¬ 
lowed  that  there  is  no  real  analogy  between  the  California  Geysers  and 
those  in  Iceland,  where  the  name  originated.  The  principal  locality  is 
in  a  side-gorge,  known  as  the  Geyser  Canon,  opening  into  the  canon 
of  Pluton  River,  itself  a  tributary  of  Russian  River.  Its  elevation  was 
not  measured  by  us,  but  it  is  said  to  be  1700  feet  above  the  sea-level. 
Along  this  canon  for  a  distance  of  about  a  quarter  of  a  mile,  and  over 
an  area  of  several  acres,  numerous  springs  and  steam  jets  occur,  the 
water  having  a  temperature  of  from  200°  to  207°  in  the  various  open¬ 
ings  into  which  the  thermometer  could  be  inserted.  In  many  localities 
there  is  no  water  running,  but  jets  of  steam  issue,  wdiich  appear  to 
have  been  under  high  pressure;  from  one  hole  about  two  feet  in  diam¬ 
eter,  it  escapes  with  a  loud  noise,  like  that  from  the  escape-pipe  of  a 
high-pressure  steamboat,  and  it  is  hence  called  the  Steamboat  Geyser. 


94 


GEOLOGY  OF  THE  COAST  KANGES 


Both  the  water  and  the  steam  are  highly  charged  with  sulphuretted 
hydrogen  and  sulphurous  acid,  and  the  waters  hold  in  solution  a  great 
variety  of  salts,  especially  sulphates  of  iron,  lime,  and  magnesia ; 
these  salts,  as  well  as  crystallized  sulphur,  are  deposited  over  the  rocks 
in  the  caiion,  giving  them  a  peculiar  and  vivid  coloration,  which  is  per¬ 
haps  the  most  striking  feature  of  the  place.  Quite  extensive  deposits 
of  sulphur  occur  farther  down  the  canon  and  are  known  as  the  “  Sul¬ 
phur  Banks.” 

The  surrounding  rocks  are  entirely  metamorphic  sandstones,  and 
silicious  slates  of  the  Cretaceous  series,  and  these  are  constantly  under¬ 
going  a  variety  of  chemical  changes  caused  by  the  action  of  the  hot 
water  and  steam.  The  iron  held  in  solution  by  some  of  the  springs 
comes  in  contact  with  water  holding  sulphuretted  hydrogen  and  an  ink- 
black  precipitate  of  sulphuret  of  iron  takes  place,  which  fills  one  reser¬ 
voir  in  the  rocks  known  as  the  Witches’  Cauldron,  and  boils  and  seethes 
with  a  most  unearthly  smell  and  appearance./  The  rock,  in  some  places, 
appears  as  if  so  thoroughly  leached  by  the  hot  water  that  only  the  silica 
remains  behind  as  a  sort  of  skeleton,  while  large  deposits  are  formed 
of  silicious  matter,  resembling  putty  in  appearance  and  consistency. 
These  changes  have  the  appearance  of  taking  place  quite  rapidly,  and 
we  were  informed  by  Mr.  McDonald  that  the  ground  has  slacked  away 
and  sunk  several  feet  (twenty-five  or  thirty,  he  thought)  around  the 
largest  spring  within  the  past  ten  years.  All  the  deposits  around  the 
springs  are  charged  with  acid  salts  and  free  sulphuric  acid,  and  a  visit 
to  the  place  is,  as  may  be  supposed,  ruinous  to  boot  and  shoe  leather. 

The  most  exaggerated  accounts  have  been  published  of  this  canon 
and  its  springs  ;  but  the  reality  is  sufficiently  interesting  to  well  repay 
a  visit,  especially  from  those  to  whom  phenomena  of  this  kind  are  new. 
It  is  said-that  the  quantity  of  water  and  steam  is  increased,  and  the  gene¬ 
ral  effect  of  the  scene  much  enhanced,  by  the  saturation  of  the  ground 
with  water  from  the  winter  rains ;  and,  as  we  saw  it  at  the  end  of  the 
dry  season,  we  were  probably  there  just  at  the  time  when  the  phenomena 
were  least  striking.  Certainly  there  were  no  jets  of  water  rising  high 
in  the  air,  as  has  been  asserted,  and  nothing  like  the  quantity  of  water 
delivered  which  issues  at  the  Steamboat  Springs  near  Washoe  Lake,  in 
[Nevada. 


NORTH  OF  THE  BAY  OF  SAN  FRANCISCO. 


95 


The  “  Little  Geysers”  are  in  character  like  the  larger  ones,  except  that, 
instead  of  issuing  along  the  bottom  of  a  canon,  they  occur  scattered 
over  a  gently  sloping  side-hill.  They  are  about  four  miles  farther  up 
the  Pluton  Canon,  at  an  estimated  height  of  2100  to  2200  feet  above 
the  sea,  and  near  the  furnace  of  the  Pioneer  Mine.  All  of  the  effects 
seen  at  the  larger  springs  may  be  observed  at  the  Little  Geysers.  A 
great  variety  of  metamorphic  sandstones  occur  here,  in  all  stages  of 
decomposition  and  chemical  change;  of  these  rocks  a  careful  examina¬ 
tion  should  be  made. 

There  will  be  no  difficulty  in  understanding  the  origin  of  these  phe¬ 
nomena  when  we  consider  that  they  are  displayed  along  a  line  of  former 
volcanic  activity,  and  where  even  now  the  igneous  forces  are  not  en¬ 
tirety  dormant.  A  belt  of  eruptive  rock,  of  which  Mount  St.  Helena 
is  the  culminating  point,  extends  through  on  the  west  side  of  Clear 
Lake  down  to  Suisun  Bay,  and  a  line  of  more  recent  volcanic  action 
may  be  traced  from  near  the  Geysers  to  Clear  Lake,  and  thence  trans¬ 
versely  across  the  Coast  Ranges  to  the  Sacramento  V alley,  along  which 
great  accumulations  of  pumice,  scoriae,  and  obsidian,  or  volcanic  slag, 
may  be  found,  as  well  as  numerous  hot  springs  like  those  at  the  Gey¬ 
sers,  only  on  a  smaller  scale.  The  dependence  of  the  Geysers  for  their 
activity,  in  part,  on  the  recurrence  of  the  rainy  season,  as  is  stated  on 
good  authority,  indicates  clearly  that  the  water,  percolating  down 
through  the  fissures  in  the  rocks,  meets  with  a  mass  of  subterranean 
lava  not  yet  entirety  cooled  off,  and  becoming  intensely  heated,  under 
pressure,  finds  its  way  to  the  surface  again  along  a  line  of  fissure  con¬ 
necting  with  the  bottom  of  Geyser  Canon ;  in  this  heated  condition  it 
has  a  powerful  action  on  the  rocks  and  the  metallic  sulplmrets  which 
the}^  contain,  especially  on  the  sulphuret  of  iron  everywhere  so  abun¬ 
dantly  diffused  through  the  formation,  and  so  dissolves  them  and  brings 
them  up  to  the  surface,  to  be  again  partly  redeposited  as  the  solution  is 
cooled  down  by  contact  with  the  air.  Phenomena  of  the  same  kind  as 
those  observed  at  the  Geysers,  and  sometimes  even  on  a  larger  scale, 
are  exhibited  all  throughout  the  now  almost  extinct  volcanic  regions  of 
California  and  Hevada;  even  on  Mount*  Shasta  the  last  expiring  ef¬ 
forts  of  this  once  mighty  volcano  may  be  traced  in  the  solfatara  action 
still  going  on  near  the  summit,  and  which  is  undoubtedly  due  to  the 


9G 


GEOLOGY  OF  TIIE  COAST  RANGES 


melting  snow  finding  its  way  down  to  the  heated  lava  or  other  volcanic 
materials  below,  in  the  interior  of  what  was  once  the  crater,  from  and 
around  which  a  mass  of  erupted  matter  has  been  poured  forth  and  piled 
up  to  the  height  of  several  thousand  feet. 

In  spite  of  the  heated  and  acid  character  of  the  ground  in  the  imme¬ 
diate  vicinity  of  the  hot  springs  at  the  Geysers,  a  species  of  grass  grows 
there,  and  the  same  has  been  noticed  elsewhere  in  similar  localities.  It 
has  been  described  by  Mr.  Bolander  as  the  Panicum  thermale.  Several 
low  forms  of  vegetation  grow  in  the  hot  water  and  on  the  surfaces  ex- . 
posed  to  the  hot  steam.  One  species,  of  a  vivid  green  color,  a  sort  of 
conferva,  was  found  on  surfaces  exposed  alternately  to  the  intensely 
hot  steam  and  the  cold  air,  as  the  former  was  blown  away  by  the  wind. 
It  was  seen  in  the  water  at  the  temperature  of  200°,  and  abundantly 
where  it  was  exposed  constantly  to  a  temperature  of  190°  to  195°,  and 
several  low  forms  of  algse,  as  well  as  the  former  species,  were  abundant 
in  the  acid  waters  of  the  stream,  where  the  temperature  ranged  from 
120°  to  180°,  although  thriving  best  at  from  125°  to  130°.  A  farther 
notice  of  these  plants  will  be  found  in  the  Botanical  Report  of  Professor 
Brewer. 

Some  explorations  have  been  made  around  the  lower  end  of  Clear 
Lake,  more  particularly  for  the  purpose  of  getting  an  idea  of  the  very 
interesting  locality  of  borax,  which  is  found  in  this  region. 

Clear  Lake  is  about  sixty-five  miles  northwest  of  Suisun  Bay,  and 
about  thirty-six  miles  from  the  Pacific.  It  is  believed  to  be  about 
twenty-five  miles  long,  but  has  never  been  surveyed,  so  that  its  shape 
and  size  are  not  accurately  known.  It  lies  so  that  its  greatest  longi¬ 
tudinal  extension  is  nearly  parallel  with  the  strike  of  the  strata  in  this 
region,  or  northwest  and  southeast;  the  lower  half,  in  length,  is  com¬ 
paratively  narrow,  being  not  over  two  miles  wide  for  a  distance  of 
eight  miles  from  its  southeast  end.  Beyond  this,  it  expands  out  into  a 
broad,  almost  circular  area,  surrounded  on  all  sides  by  high  hills, 
which  on  the  northeastern  side  come  close  down  to  the  water;  on  the 
west  and  northwest  there  is  a  plateau  of  rolling  land  between  the  lake 
and  the  mountains,  which,  although  dry,  has  a  pretty  good  soil,  and 
where  there  is  a  small  settlement. 

At  the  angle  where  the  narrow  part  of  the  lake  opens  out  to  the  west 


NORTH  OF  THE  BAY  OF  SAN  FRANCISCO. 


97 


is  a  high  mountain,  which  comes  down  with  a  precipitous  front  to  the 
water,  and  which  is  supposed  to  be  about  2500  feet  above  the  lake- 
level.  It  is  called  the  “  Uncle  Sam  Mountain,”  and,  as  seen  from  the 
opposite  side  of  the  lake,  it  appears  to  be  made  up  of  a  closely  folded 
synclinal  mass,  probably  of  somewhat  metamorphic  Cretaceous  sand¬ 
stones.  On  the  southwest  side,  and  to  the  southeast,  volcanic  materials 
and  rocks  occupy  the  surface,  as  is  well  seen  in  a  crater-like  depression 
on  the  southwest  side  of  the  narrow  arm  of  the  lake,  called  “  Thurston’s 
Lake,”  which  is  partly  covered  by  water,  and  surrounded  on  all  sides 
by  high  cliffs  of  volcanic  rocks,  appearing  as  if  it  might  have  been  one 
of  the  vents  from  which  the  eruptive  matter,  obsidian,  ashes  and  pu¬ 
mice,  so  abundant  in  this  region,  were  ejected.  On  the  eastern  side  of 
the  narrow  arm  of  Clear  Lake,  nearly  opposite  to,  and  about  four  miles 
distant  from,  Thurston’s  Lake,  is  a  large  accumulation  of  volcaific  ma¬ 
terials,  with  much  obsidian  and  pumice.  In  fact,  all  through  the  chain 
of  the  Coast  Ranges  in  this  direction,  down  Grizzly  Canon  to  Bear 
Valley,  on  the  trail  to  Colusi,  there  are  hot  springs  and  the  remains  of 
solfatara  action,  indicating  strongly  a  cross-fracture  in  this  region, 
through  which  the  volcanic  agencies  have  made  themselves  percep¬ 
tible,  and  which  probably  connects  on  the  southwest  with  the  Geysers, 
thus  forming  a  line  of  volcanic  action  nearly  if  not  quite  across  the 
chain. 

Among  the  evidences  of  the  former  working  of  volcanic  forces  in 
this  region,  there  is  nothing  more  interesting  and  remarkable  than  the 
so-called  “  Borax  Lake”  and  its  vicinity.  This  lake  occupies  a  depres¬ 
sion  on  the  east  side  of  the  narrow  arm  of  Clear  Lake,  from  which  it 
is  separated  by  a  low  ridge  of  volcanic  materials,  lying  loosely  heaped 
together,  and  consisting  of  scoriae,  obsidian,  and  pumice.  The  Borax 
Lake  is  of  variable  dimensions,  according  to  the  season  of  the  year  and 
the  comparative  dryness  of  the  season.  When  examined  (September, 
1863),  the  water  occupied  an  area  about  4000  feet  long,  and  1800  feet 
wide  in  the  widest  place,  and  its  shape  was  irregularly  oval,  its  longer 
axis  being  turned  in  the  direction  of  east  and  west,  magnetic ;  it  has 
once  extended  nearly  twice  as  far  to  the  southeast,  as  the  ground  is 
hardly  raised  above  its  present  level  in  that  direction  for  nearly  a  mile. 
The  lake  is  said  to  have  been  entirely  dry  during  the  summer  before 

GEOL.  VOL.  T. — 13 


98 


GEOLOGY  OF  THE  COAST  RANGES 


the  great  rains  of  1861-62.  In  1863  the  water  was  about  three  feet 
deep. 

The  existence  of  this  lake  was  first  made  known  to  the  world  by  Dr. 
J.  A.  Veatch,  who  examined  it  in  September,  1856,  and  detected  the 
presence  of  borax  in  its  waters;  but  it  was  not  until  some  months  after¬ 
wards  that  the  existence  of  a  large  bed  of  crystals  ot  this  valuable  ma¬ 
terial  in  the  bottom  of  the  lake  was  discovered.  The  land  about  here 
has  been  located  by  the  c<  California  Borax  Company,”  the  agents  of 
which  have  caused  explorations  to  be  made,  have  had  the  waters  care¬ 
fully  analyzed,  and  were,  in  1864,  preparing  to  manufacture  borax  on 
a  large  scale. 

The  water  collected  from  the  Borax  Lake,  in  September,  1863,  as 
analyzed  by  G.  E.  Moore,  contained  2401,56  grains  of  solid  matter  to 
the  gallon,  of  which  about  one-lialf  was  common  salt,  one-quarter  car¬ 
bonate  of  soda,  and  the  remainder  chiefly  borate  of  soda,  there  being 
281.48  grains  of  the  anhydrous  biborate,  equal  to  535.08  of  crystallized 
borax,  to  the  gallon.  Traces  of  iodides  and  bromides  were  also  detected. 
A  sample  of  water  taken  from  the  interior  of  a  coffer-dam  sunk  in  the 
middle  of  the  lake,  and  which  had  been  allowed  to  fill  by  percolation 
from  the  bottom  upwards,  was  found  to  be  more  concentrated,  yielding 
3573.46  grains  of  solid  matter  to  the  gallon;  but  it  contained  nearly 
the  same  ingredients,  and  in  the  same  proportions,  as  the  water  of  the 
lake  itself.  The  borax,  being  the  least  soluble  substance  contained  in 
any  notable  quantity  in  the  water,  has  in  process  of  time  crystallized 
out  to  a  considerable  extent,  and  now  exists  in  the  bottom  of  the  lake 
in  the  form  of  distinct  crystals,  which  are  of  all  sizes,  from  microscopic 
dimensions  up  to  two  or  three  inches  across.  These  crystals  form 
a  layer  immediately  under  the  water,  intermixed  with  blue  mud,  of 
varying  thickness;  as  observed  in  the  coffer-dam  sunk  in  1863,  the 
layer  of  crystals  was  about  eighteen  inches  thick,  and  beneath  it  was 
mud  without  crystals.  The  thickness,  however,  of  the  deposit  is 
undoubtedly  very  variable,  and  there  are,  in  places,  several  layers  of 
them  separated  by  beds  of  clay  or  mud.  It  is  believed,  by  those  who 
have  examined  the  bottom  of  the  lake,  that  several  million  pounds  of 
borax  may  be  obtained  from  it  by  means  of  movable  coffer-dams,  at  a 
moderate  expense,  and  so  as  to  yield  a  handsome  profit  to  those  en- 


NORTH  OF  THE  BAY  OF  SAN  FRANCISCO. 


99 


gaged  in  the  enterprise.  How  much  of  a  supply  of  water  could  be 
obtained  by  boring,  and  what  its  quality  would  be,  can  hardly  be  settled 
in  any  other  way  than  by  actual  experiment. 

Lying  about  a  mile  beyond  the  ridge  which  borders  the  Borax  Lake 
on  the  northeast,  and  at  the  foot  of  a  shorter  arm  of  Clear  Lake  which 
extends  off  to  the  southeast  parallel  with  the  longer  one,  is  an  interest¬ 
ing  locality  where  solfatara  action  is  still  going  on,  and  where  a  large 
amount  of  sulphur  has  accumulated.  This  is  called  the  “  Sulphur 
Banks.”  It  consists  of  a  much  decomposed  volcanic  rock,  fissured  in 
innumerable  places,  through  which  fissures  steam  and  gas  are  constantly 
issuing,  and  all  over  and  through  which  large  quantities  of  sulphur 
have  been  deposited,  so  as  to  give  the  mass,  from  a  little  distance,  the 
appearance  of  being  entirely  composed  of  this  material.  Into  some  of 
the  cavities  a  pole  may  be  inserted  for  several  feet,  and  they  are  often 
lined  with  fine  crystallizations  and  stalactites  of  sulphur.  Ho  doubt  a 
large  quantity  of  this  material  could  be  obtained  here,  and  the  time 
will  probably  come  when  it  will  be  made  available.  It  is  the  largest 
deposit  which  we  have  seen  in  the  State,  covering  several  acres  of 
ground ;  but  to  ascertain  its  value  and  determine  the  quantity  of  pure 
sulphur  it  contains,  it  would  have  to  be  dug  into  at  various  points. 

Hear  the  sulphur  bank  just  at  the  edge  of  the  lake  is  a  hot  spring, 
of  which  the  outlet  is,  even  at  low  water,  partly  beneath  the  lake,  so 
that  the  amount  which  flows  from  it  cannot  be  ascertained  without 
some  expenditure  to  keep  out  the  surrounding  water.  The  flow  of 
this  spring  seems  to  be  quite  variable  at  different  seasons,  and  proba¬ 
bly  the  amount  of  materials  it  holds  in  solution  is  far  from  constant. 
Dr.  Veatch  found  the  area  over  which  hot  water  Was  percolating  through 
the  sand  to  be  150  by  75  feet  in  dimensions;  at  the  time  of  our  visit  it 
was  much  less;  nor  was  the  estimated  yield  anything  like  as  great  as 
he  made  it,  namely,  three  hundred  gallons  per  minute. 

The  water  of  this  spring,  as  analyzed  by  Mr.  Moore,  is  found  to  be 
of  a  remarkable  character;  his  analysis  is  subjoined: 


Crains  in  one  gallon. 


Chloride  of  potassium, . 
Chloride  of  sodium, 


Iodide  of  magnesium,  . 
Bromide  of  magnesium 


.09 

trace. 


100 


GEOLOGY  OF  T11E  COAST  RANGES 


Bicarbonate  of  soda,  ...  .  .  .  .  .  76.96 

Bicarbonate  of  ammonia,  ......  107.76 

Biborate  of  soda,  ........  103.29 

Sulphate  of  lime,  .  ...  .  .  .  .  .  trace. 

Alumina,  .........  1.26 

Carbonic  acid  (free),  ......  .  36.37 

Silicic  acid,  .........  8.23 

Matters  volatile  at  a  red  beat,  .....  65.77 


484.35 

Iii  this  table  the  constituents  are  necessarily  calculated  as  anhydrous 
salts ;  the  biborate  of  soda,  however,  contains  about  47  per  cent,  of 
water  when  crystallized,  and  the  103.29  grains  given  above  correspond 
to  195.35  of  crystallized  borax.  The  most  extraordinary  feature  in  the 
above  analysis  is  the  very  large  amount  of  ammoniacal  salts  shown  to 
be  present  in  this  water,  in  this  respect  exceeding  any  natural  spring- 
water  which  has  ever  been  analyzed.  Mr.  Moore  thinks  that,  as  in  the 
case  of  the  boracic  acid  waters  of  Tuscany,  this  ammoniacal  salt  may 
be  separated  and  made  available  for  economical  purposes.  This  locality 
is  worthy  of  a  most  careful  examination  to  ascertain  how  considerable 
a  How  of  water  can  be  depended  on. 

The  rocks  in  the  vicinity  of  Clear  Lake,  when  not  of  volcanic  origin,  . 
belong  to  the  Cretaceous  system,  and  are  the  continuation  of  a  great 
belt  of  strata  of  this  age,  which  commences  at  Benicia  and  stretches 
off  to  the  northwest  for  an  indefinite  distance,  apparently  coming  out 
to  the  ocean  in  the  neighborhood  of  Cape  Mendocino.  Having  fol¬ 
lowed  up  Hapa  Valley,  by  Mount  St.  Helena,  to  the  Geysers  and  Clear 
Lake,  giving  what  information  we  possess  in  regard  to  the  western 
portion  of  the  Coast  Ranges  north  of  the  Bay  of  San  Francisco,  it  re¬ 
mains  to  add  some  observations  on  the  eastern  side  of  the  region  in 
question. 

A  system  of  ridges  begins  at  Benicia  and  stretches  northwest  along 
the  eastern  side  of  Hapa  Valley,  but  the  chain  is  not  known  by  any 
general  name.  Mount  St.  Helena  belongs  to  this  range  and  is  its  cul¬ 
minating  point  south  of  Clear  Lake.  These  mountains  are  a  continu¬ 
ation  of  the  Monte  Diablo  Range,  and  the  mass  of  them  is  probably  of 
Cretaceous  age ;  but  volcanic  rocks  are  also  extensively  developed 


NORTH  OF  TIIE  BAY  OF  SAN  FRANCISCO. 


101 


here,  Loth  in  the  form  of  solid  lava  and  of  sedimentary  materials,  or 
such  as  have  been  thrown  out  in  the  form  of  ashes,  pumice,  and  the  like, 
and,  having  fallen  into  water,  have  assumed  in  their  deposition  a  strati¬ 
fied  appearance. 

The  termination  of  this  range  at  Benicia  is  of  unaltered  Cretaceous 
strata,  much  broken,  and  forming  rounded  hills,  destitute  of  trees. 
Here,  as  in  Contra  Costa  County,  the  Cretaceous  is  well  represented, 
both  by  the  bluish  clay  shales,  with  interstratified  beds  of  argillaceous 
limestone,  and  by  the  overlying  masses  of  blue  and  yellow  sandstones, 
the  latter  in  very  heavy  beds.  The  shales  are  seen  everywhere  along 
the  shore  and  in  the  deeply  eroded  valleys.  As  usual,  this  member  of 
the  series  is  very  poorly  supplied  with  fossils,  but  a  few  characteristic 
forms  were  discovered  by  Mr.  Esmond  near  the  arsenal ;  among  them 
Ammonites  Batesii ,  that  common  and  characteristic  species  of  the  older 
beds  of  the  Cretaceous. 

On  rising  into  the  hills  back  of  Benicia  the  sandstones  are  met  with, 
the  outcropping  of  the  strata  being  plainly  indicated  by  the  lines  of 
weather-worn  blocks  extending  over  the  rounded  ridges.  The  strike 
is  very  irregular,  as  if  the  formation  had  been  extensively  faulted ;  it 
varies  from  H.  15°  W.  to  H.  60°  W.,  and  the  dip  is  usually  to  the 
southwest.  Intermediate  between  these  two  sets  of  strata,  the  sand¬ 
stones  and  shales,  are  beds  of  passage,  consisting  of  interstratified  layers 
of  both  kinds  of  rock,  and  it  appears  to  be  in  this  position  that  the 
beds  of  hydraulic  limestone  occur,  which  have  been  so  extensively 
worked  near  Benicia. 

Although  fossils  are  so  infrequent  through  the  whole  series  of  Cre¬ 
taceous  beds  of  this  region,  in  comparison  with  the  widespread  area 
which  the  formation  covers,  yet  the  sandstones  are  much  better  sup¬ 
plied  with  these  than  the  underlaying  shales.  Mr.  Rfimond  discovered 
a  locality,  about  half  a  mile  north-northeast  of  Benicia,  where  a  bed  of 
conglomerate  occurred,  several  feet  thick,  and  filled  with  fragments  of 
shells,  among  which  Trigonia  Evansii  was  the  most  abundant;  this  is  a 
very  characteristic  and  widely  distributed  fossil  in  the  Lower  Cretace¬ 
ous  of  the  Pacific  coast,  ranging  from  Central  California  to  Vancouver’s 
Island.  This  Trigonia  stratum  was  traced  from  Benicia  to  Suisun  Bay, 


GEOLOGY  OF  THE  COAST  RANGES 


102 

and  was  afterwards  found  on  the  opposite  side  of  the  Straits  of  Car- 
quines,  at  Bull’s  Head  Point. 

Hearty  the  whole  of  the  peninsula  on  which  Benicia  is  situated,  for 
some  twelve  miles  towards  the  interior,  is  made  up  of  these  quite  unal¬ 
tered  Cretaceous  rocks,  forming  low,  rounded  hills  which  are  quite  hare 
of  trees.  There  are,  however,  two  belts  of  metamorphic  rock  extending 
through  this  region,  one  of  them  forming  lowr  hills  on  its  eastern  edge, 
the  other  and  principal  one  beginning  about  three  miles  north  of  Be¬ 
nicia,  and  extending  in  a  direction  of  H.  53°  W.  This  latter  belt  widens 
to  the  northwest  and  disappears  at  the  edge  of  the  hills,  in  that  direc¬ 
tion,  which  is  that  of  a  high  metamorphic  ridge  west  of  Carnero  Creek. 
The  rock  is  very  line-grained  and  durable,  and  forms  sharp  ridges  when 
denuded. 

The  unaltered  Cretaceous  strata  in  the  vicinity  of  Benicia  and  Vallejo, 
and  on  the  west  side  of  the  metamorphic  belt  just  noticed,  have  a  strike 
of  H.  55°  to  58°  W.,  and  dip  to  the  southwest  at  an  angle  of  from  30° 
to  60°.  On  the  east  side  of  the  metamorphic  the  rocks  are  tilted  up  at 
a  higher  angle,  and  have  an  inclination  to  the  northwest  and  a  more 
northerly  direction. 

A  Post-Tertiary  deposit,  made  up  of  beds  of  gravel,  sand,  clay,  and 
oyster-shells,  rests  horizontally  upon  the  upturned  edges  of  the  Creta¬ 
ceous  at  several  localities  around  Benicia.  These  are  similar  to  the 
beds  noticed  as  occurring  on  the  shore  between  Martinez  and  Bull’s 
Head  Point,  which  contain  fragments  of  bones  of  large  animals  and 
rolled  Tertiary  shells.  Similar  beds,  with  oysters,  wrere  observed  on 
San  Pablo  Bay  between  Point  Pinole  and  the  Embarcadero ;  at  this 
locality  the  beds  containing  oysters,  which  rest  horizontally  on  upturned 
strata  of  the  Tertiary,  are  elevated  twenty  feet  above  the  level  of  the 
water  in  the  bay.  At  Benicia  also  there  has  been  an  elevation  of  sev¬ 
eral  feet  since  these  oyster-beds  were  deposited.  With  the  shells  of 
oysters,  those  of  other  species,  all  now  living  in  the  waters  of  the  bay, 
are  found.  These  deposits  evidently  belong  to  the  Post-Pliocene,  and 
they  are  of  the  same  age  as  the  beds  of  gravel  with  boulders  of  gray 
sandstone,  containing  the  bones  of  th6  mastodon  and  horse,  which 
occur  at  Bottle  Hill  near  Benicia.  Tertiary  sandstones  also  exhibit 
themselves  in  very  limited  exposures  near  Suscol. 


NORTH  OF  THE  BAY  OF  SAN  FRANCISCO. 


103 


At  about  twelve  miles  north  of  Benicia,  the  older  rocks  become 
covered  with  volcanic  materials,  which  are  mostly  stratified,  and  which 
appear  to  rest  conformably  on  the  Cretaceous.  Between  the  volcanic 
and  the  Cretaceous  there  is,  in  some  places  at  least,  and  perhaps  all 
through  this  region,  a  deposit  of  Tertiary  rocks  exclusively  of  sedimen¬ 
tary  origin,  as  is  distinctly  seen  at  Suscol,  but  the  exact  range  and  ex¬ 
tent  of  these  various  formations,  and  how  far  the  Cretaceous  has  been 
elevated  and  denuded  before  the  deposition  of  the  newer  groups,  re¬ 
mains  to  be  investigated.  It  is  probable  that  the  most  extensive  dis¬ 
turbances  of  the  Cretaceous,  as  also  the  larger  portion  of  the  metamor- 
phic  action  upon  it,  had  taken  place  before  the  Tertiary  marine  and  vol¬ 
canic  beds  were  deposited. 

In  the  range  of  hills  to  the  left  of  the  road  from  Benicia  to  Suisun, 
a  few  miles  north  of  the  former  place,  the  volcanic  beds  ar.e  dark- 
colored  and  have  a  texture  varying  from  compact  to  cellular.  They 
dip,  near  the  road,  at  an  angle  of  about  40°  to  the  southwest  ;  but  are, 
in  general,  irregularly  disturbed,  and  the  adjacent  Cretaceous  beds  are 
broken  and  bent,  the  two  formations  being  so  intermixed  that  it  is 
not  easy  to  trace  out  their  boundaries.  These  rocks  closely  resemble 
the  altered  volcanic  rocks  seen  near  Kirker’s  Pass,  in  Contra  Costa 
County. 

In  the  vicinity  of  Rockville,  the  same  formation  occurs ;  but  here 
consists  of  heavy  beds  of  stratified  volcanic  ashes,  which  have  a  nearly 
horizontal  position.  Their  color  is  white  or  light-yellowish,  and  they 
often  are  brecciated  in  structure,  and  have  many  fragments  of  pumice 
and  darker-colored  trachytic  material  scattered  through  their  mass. 

The  unaltered  Cretaceous  rocks  extend  from  Benicia,  on  the  west  of 
this  volcanic  range,  to  a  point  three  miles  southwest  of  Rockville, 
where  they  are  seen  cropping  out  at  the  base  of  Elkhorn  Peak.  Be¬ 
yond  this,  to  the  northwest,  all  along  between  this  peak  and  the  Twin 
Sisters,  and  connecting  still  farther  in  that  direction  with  the  range  of 
Mount  St.  Helena,  the  volcanic  beds  form  the  mass  of  the  hills.  The 
region  occupied  by  these  eruptive  rocks  is  very  broken  and  rugged,  and 
the  ridges  rise  higher  as  we  go  northwest.  A  great  variety  of  volcanic 
materials  may  be  observed  here,  and  especially  of  those  which  have 
been  ejected  under  water,  or  which  have  fallen  into  water  and  have 


104 


GEOLOGY  OF  THE  COAST  RANGES 


thus  been  made  to  assume  a  stratified  form.  Not  only  has  the  true 
character  of  these  materials  been  thus  masked  by  their  deposition  from 
water,  but  they  have  undergone  still  farther  changes  by  the  metamor- 
phic  action  of  hot  water,  steam,  and  gases  on  them  since  their  forma¬ 
tion;  and  the  result  has  been  a  most  complicated  series  of  rocks,  which 
offer  every  possible  variety  of  texture  and  color,  and  require  a  most 
careful  investigation  of  their  chemical  composition  before  they  can  well 
be  classified  or  named.  These  strata  appear  also  to  have  undergone 
mechanical  disturbances  since  their  deposition,  their  inclination  being 
usually  to  the  west.  They  may  be  well  studied  around  the  head  of 
Green  Valley. 

North  of  Suisun  commences  another  series  of  hills,  which  has  re¬ 
ceived  the  name  of  the  “  Pelevo  Hills,”  at  their  southeastern  end,  but 
which  extend  northwest  and  become  merged  in  the  chain  known  as 
the  “  Vacca  Mountains,”  which  is  the  name  given  to  the  ridges  here 
bounding  the  Sacramento  Valley  on  the  western  side. 

The  Pelevo  Hills  form  a  kind  of  spur  or  side-range,  extending  south¬ 
east  from  the  main  ridge  of  the  Vacca  Mountains;  they  are  destitute  of 
trees  and  shrubs.  These  hills  are  made  up  of  Cretaceous  strata,  unal¬ 
tered  and  containing  but  few  fossils  ;  the  strike  of  the  beds  is  generally 
about  northwest  and  southeast,  and  the  dip  to  the  northeast  and  vari¬ 
able  in  amount. 

The  well-known  “  Suisun  marble”  occurs  in  these  sandstones,  and 
is  evidently  a  deposit  from  calcareous  springs.  It  is  of  a  deep  brown¬ 
ish-yellow  color,  with  a  banded  structure,  and  is  a  very  elegant  orna¬ 
mental  stone,  which  would  be  much  sought  for  if  it  could  be  ob¬ 
tained  in  masses  of  any  considerable  size,  which  does  not  seem  to  be 
possible;  it  has  also  been  burned  for  lime  to  some  extent.  A  short 
distance  from  the  quarry  springs  occur,  which  hold  much  lime  in  solu¬ 
tion,  and  are  now  forming  an  extensive  deposit  of  tufa;  these  springs 
have  evidently  been  at  a  former  time  much  more  copious  than  they 
now  are. 

From  the  Twin  Sisters  the  volcanic  range  extends  northward  for 
many  miles,  bending  a  little  to  the  west;  it  forms  a  thick  mass  of  hard¬ 
ened  ashes,  dark-colored  scoriae,  and  peculiar  feldspathic  rocks,  inter- 
stratified  with  beds  of  basaltic  lava,  all  having  a  slight  dip  to  the  west. 


NORTH  OF  THE  BAY  OF  SAN  FRANCISCO. 


105 


These  various  beds  are  finely  exposed  on  the  west  side  of  Wooden 
Valley. 

The  Cretaceous  formation,  which  is  seen  cropping  out  near  the  north¬ 
eastern  base  of  the  Twin  Sisters,  is  continuous  from  that  place  as  far 
north  as  Capel  Valley,  at  which  point  it  becomes  metamorphic  and 
broken.  The  hills  lying  between  the  Sacramento  and  Suisun  Valleys 
are  also  Cretaceous,  and  they  appear  to  form  a  line  of  foot-hills  along 
a  high  Cretaceous  ridge,  made  up  of  unaltered  shales  and  sandstones, 
running  nearly  northwest  and  southeast,  and  extending  from  Suisun 
Bay  to  Puta  Creek.  This  range  is  about  3500  feet  high,  and  the  ridge 
along  the  summit  is  formed  by  lieavy-bedded  sandstones ;  it  is  quite  a 
remarkable  feature  in  this  part  of  the  Coast  Ranges,  that  so  high  and 
extensive  a  ridge  should  be  made  up  of  unaltered  rocks.  The  road 
leading  from  Suisun  Bay  to  Puta  Creek,  through  Gordon  Valley  and 
Rag  Canon,  skirts  this  ridge  on  the  western  side.  The  dip  of  this 
mass  of  strata  is  to  the  northeast,  and  the  strike,  which  is  V.  35°  W. 
to  the  east  of  Gordon  Valley,  gradually  becomes  more  northerly  as  we 
approach  Puta  Creek,  where  it  is  about  V.  50°  E. ;  the  dip  varies  from 
35°  to  80°. 

Rear  the  head  of  Wooden  Valley,  there  is  a  mass  of  serpentine,  some 
two  or  three  miles  in  length,  which  appears  to  occupy  the  summit  of 
an  anticlinal  axis,  as  the  strata  dip  to  the  west,  on  the  other  side  of 
Suisun  Creek.  The  rocks  around  Capel. Valley  are  also  considerably 
metamorphosed,  and  contain  some  beds  of  conglomerate. 

Puta  Creek  cuts  its  way  through  the  great  Cretaceous  ridge  noticed 
above,  nearly  at  right-angles  with  the  strike  of  the  beds,  thus  present¬ 
ing  a  fine  section  of  the  strata  from  Rag  Canon  as  far  as  the  northern 
end  of  Pleasant  Valley.  In  following  this  section  from  the  west,  seve¬ 
ral  hundred  feet  in  thickness  of  clay-shales  and  slaty  sandstones  are 
crossed,  with  thin  layers  of  calcareous  and  ferruginous  sandstones,  but 
the  usual  argillaceous  limestones  are  comparatively  rare.  These  strata 
have  been  twisted  and  faulted,  but  not  chemically  changed.  Beyond 
this,  we  meet  an  enormous  thickness  of  sandstones,  the  strata  stand¬ 
ing  nearly  vertical,  and  forming  on  each  side  of  the  creek  grand  and 
almost  perpendicular  cliffs,  which  rise  to  the  height  of  from  1200  to 
1500  feet.  Here  and  there  occurs  a  thin  layer  of  conglomerate,  made 

OEOL.  VOL.  I. — 14 


106 


GEOLOGY  OF  THE  COAST  RANGES 


up  of  rounded  pieces  of  the  argillaceous  limestone  found  in  the  lower 
member  of  the  series,  with  small  pebbles  of  jaspery  rock,  mixed  with 
a  few  broken  shells,  the  whole  cemented  by  sand  and  clay.  Generally 
through  this  region  the  Cretaceous  rocks  are  almost  destitute  of  fossils. 

At  the  head  of  Pleasant  Valley,  the  strata  are  overlaid  by  beds  of 
volcanic  ashes,  interstratified  with  gravels,  the  whole  series  being  con¬ 
formable  and  dipping  at  a  low  angle  to  the  east.  They  appear  to  be  of 
Pliocene  age,  and  identical  in  most  respects  with  the  sedimentary-vol¬ 
canic  beds  to  the  north  of  Kirker’s  Pass.  A  dyke  of  fine-grained,  com¬ 
pact,  black,  basaltic  lava  cuts  through  these  beds ;  from  this  enormous 
blocks  have  rolled  down  into  the  bed  of  the  creek.  This  same  dyke  is 
seen  crowning  a  hill,  about  1500  feet  high,  a  little  eagt  of  Thurber’s 
Ranch  in  Pleasant  Valley  (Camp  85).  It  follows  a  zigzag  course,  the 
general  direction  of  which  is  about  H.  15°  E.  It  is  fractured  in  every 
direction  and  gradually  weathers  into  angular  fragments.  This  dyke 
cuts  through  the  Cretaceous  strata  without  changing  their  dip,  and  pro¬ 
ducing  but  slight  alteration  of  the  adjacent  rock  along  the  line  of  con¬ 
tact.  The  magnetic  needle  is  very  irregularly  and  extensively  affected 
by  this  rock.  Just  below  the  summit  of  this  hill,  and  a  little  to  the 
north  of  it,  is  a  bed  of  gravel,  twenty-five  feet  thick,  chiefly  made  up 
of  pebbles  of  basalt,  porphyry,  and  jasper;  those  of  the  basalt  are  from 
the  size  of  a  nut  to  that  of  the  fist,  the  others  very  small;  this  deposit 
has  been  formed  since  the  eruption  of  the  basaltic  dyke,  and  is  quite 
anomalous  in  character  and  position. 

It  is  an  important  question,  whether  the  unaltered.  Cretaceous  strata, 
which,  as  we  have  seen  above,  extend  along  the  east  edge  of  the  Coast 
Ranges  from  Benicia  northwards  for  a  considerable  distance,  contain 
workable  beds  of  coal.  Deposits  of  coaly  matter,  fragments  of  plants, 
and  masses  of  lignite  were  observed  by  us ;  but  no  regular  and  well- 
developed  beds  of  coal,  like  those  at  Monte  Diablo.  The  following 
section,  taken  on  Suisun  Bay,  a  little  north  of  the  arsenal,  by  Mr. 
RGnond,  will  show  how  these  imperfect  coal-beds  are  connected  with 
the  formation : 

Shales,  ...........  6  inches. 

Sandstone, . 2  feet  6  “ 

Thin-hedded  argillaceous  sandstone,  .  .  .  .  .  11  “ 


NORTH  OF  THE  BAY  OF  SAN  FRANCISCO. 


107 


Hurd  calcareous  sandstone, ..... 

Shales,  ........ 

Thin-bedded  sandstone  with  fragments  of  plants, 
Light  yellow  sandstone,  ..... 

Shaly  parting,  ....... 

Thin-bedded  sandstones  with  plants,  . 

Soft  sandstones,  ....... 

Clay  shales,  ....... 

Lignite, . 

Sandstones  and  shales,  thickness  not  determined. 


3  feet. 

6  inches. 
8  “ 

1  foot. 

1  inch. 
11  inches. 
10  “ 

3  “ 

6  “ 


This  is  a  specimen  of  many  sections  observed,  where  thin  beds  of 
lignite  and  strata  containing  remains  of  plants  were  intercalated  with 
the  shales  and  sandstones  of  the  Cretaceous  series.  A  good  deal  of 
exploration  for  coal  lias  taken  place  along  this  range;  but,  from  all  that 
can  be  learned,  it  would  appear  that  the  rocks  are  too  much  broken  up, 
where  such  deposits  have  hitherto  been  found,  to  admit  of  their  being 
successfully  and  continuously  worked.  The  region  has  not,  however, 
been  explored  with  sufficient  detail  by  the  Survey,  to  enable  us  to  decide 
positively  that  valuable  beds  of  coal  may  not  yet  be  found  here.  The 
absence  of  any  map  of  this  region  renders  it  impossible  to  work  out 
the  details  of  its  geology. 

The  ridges  lying  between  Petaluma  and  Sonoma,  and  between  So¬ 
noma  and  Napa,  are  made  up  of  metamorphic  rocks,  with  some  unal¬ 
tered  strata,  and  also  large  quantities  of  materials  of  volcanic  origin. 

Between  Petaluma  and  Sonoma,  the  mass  of  the  ridge  is  of  highly 
metamorphic  strata,  which  are  supposed  to  be  of  Cretaceous  age. 
Sandstones  occur  along  the  western  base,  near  Lakeville,  very  highly 
inclined,  and  destitute  of  fossils,  so  far  as  observed.  These  are  altered 
in  some  places  and  form  a  ridge  to  the  west  of  the  higher  metamor- 
phic,  from  which  they  are  separated  by  a  valley  in  which  is  a  small 
“  laguna.” 

The  higher  metamorphic  ridge  is  composed  of  rock  of  a  great  va¬ 
riety  of  different  characters.  Columnar  basalt  occurs  in  a  spur  about 
five  miles  northwest  of  Sonoma.  The  eastern  slope  of  these  ridges  is 
covered  by  volcanic-sedimentary  materials. 

About  eight  miles  due  north  of  Petaluma,  coal  occurs  in  a  ridge,  at 
the  base  of  which  there  is  much  very  hard  and  probably  volcanic  rock; 


108 


GEOLOGY  OF  THE  COAST  RANGES 


above  this  are  shales,  not  at  all  metamorphosed,  in  which  is  the  coal. 
These  shales  are  very  light,  when  dry,  and  resemble  those  seen  near 
the  coal,  at  the  Clark  Mine  near  Monte  Diablo,  and  also  near  Marsh’s; 
they  appear  to  be  of  Cretaceous  age.  The  strata  have  a  direction  a 
little  to  the  east  of  north,  and  dip  to  the  east  from  40°  to  50°,  showing 
indications  of  irregular  disturbances  since  their  deposition. 

The  Valley  of  Petaluma  extends  through  to  the  Russian  River,  being 
separated  from  that  of  the  Santa  Rosa  Creek  by  hills  so  low  that  the 
divide  can  hardly  be  recognized.  This  valley  is  in  the  direct  line  with 
the  Tertiary  strata  of  the  Contra  Costa  Hills,  and  is  probably  an  excava¬ 
tion  in  that  belt,  with  metamorphic  Cretaceous  and  eruptive  rocks  on 
both  sides. 

What  little  remains  to  be  said  with  regard  to  the  continuation  of  the 
Tertiary  and  Cretaceous  formations  over  the  vast  area  of  the  Coast 
Ranges,  to  the  north  of  the  point  at  which  our  explorations  have  ceased, 
will  be  added  in  another  part  of  this  volume. 


CHAPTER  V. 

THE  COAST  RANGES  SOUTH  OF  THE  BAY  OF  MONTEREY. 

Section  I. — Introductory  Remarks. 

Having  given,  in  the  preceding  chapters,  an  outline  of  the  geology 
of  the  region  adjacent  to  the  Bay  of  San  Francisco,  which  portion  of 
the  State  was  taken  up  first,  for  reasons  which  have  been  already  stated, 
we  pass  on  to  the  consideration  of  another  extensive  area  embraced 
within  the  Coast  Ranges,  namely,  that  which  lies  north  of  Santa  Bar¬ 
bara  Channel  and  the  Santa  Monica  Range,  and  extends  to  the  southern 
end  of  Monterey  Bay. 

This  portion  of  the  Coast  Ranges  embraces  an  extensive  territory, 
about  250  miles  long  and  from  40  to  50  broad,  including  between  10,000 
and  12,000  square  miles,  an  area  considerably  greater  than  that  of  the 
State  of  Vermont.  The  whole  of  this  region  is  of  a  mountainous  cha- 


SOUTH  OF  THE  BAY  OF  MONTEREY. 


109 


racter,  the  valleys  not  being  of  sufficient  dimensions  to  be  considered 
as  anything  else  than  subordinate  to  the  mountains,  as  they  always 
appear  very  narrow  when  compared  with  the  extent  of  the  elevated 
regions  on  each  side  of  them.  The  only  possible  exception  to  this  is 
perhaps  the  Salinas  Valley,  which  at  its  lower  end,  for  a  distance  of 
about  twenty-five  miles  from  the  mouth  of  the  river,  has  an  average 
breadth  of  from  six  to  eight  miles.  West  of  the  Salinas  and  a  line 
drawn  to  the  southeast  in  continuation  of  its  direction,  there  are  no 
valleys  which  are  wide  enough  to  be  represented  on  any  map  drawn 
on  the  small  scale  of  those  commonly  in  use  as  State  maps  of  Cali¬ 
fornia. 

Of  the  whole  of  this  extensive  area  we  know  but  little  more  than  the 
general  features  of  the  geography,  and  of  course  are  equally  deficient 
in  the  details  of  its  geology.  A  map  of  the  region  in  question  has 
been  commenced  by  Mr.  Hoffmann,  on  a  scale  of  six  miles  to  the  inch, 
partly  to  bring  together  all  that  was  known  of  its  geography,  and  partly 
that  we  might  lay  down  our  own  work  upon  it,  which  makes  some  ap¬ 
proach  to  completeness  in  the  northwestern  corner,  around  the  Bay  of 
Monterey;  but  elsewffiere  is  only  in  detached  fragments.  To  complete 
this  map,  so  as  to  show  the  main  features  of  the  topography  on  the 
scale  adopted,  would  require  at  least  two  years’  work ;  but  the  results 
would  certainly  prove  a  valuable  contribution  to  the  geography  and 
geology  of  the  State. 

The  inaccuracy  and  incompleteness  of  our  maps  prevent  us  from 
giving  any  complete  view  of  the  systems  of  mountain-ranges  existing 
within  the  area  we  now  propose  to  take  up.  Some  generalizations, 
however,  may  be  permitted,  before  entering  into  details,  as  they  are 
based  on  facts  observed,  and  will  be  useful  as  preliminary  to  what 
follows. 

It  may  first,  however,  be  stated,  that  our  explorations  in  the  portion 
of  the  Coast  Ranges  which  lies  between  Santa  Barbara  and  the  Bay 
of  Monterey,  were  made  chiefly  during  the  early  spring  of  1861,  and 
that  they  were  necessarily  of  a  very  superficial  character,  although  it 
may  be  fairly  claimed  that  the  most  was  done  which  could  be,  with  the 
limited  amount  of  time  and  means  at  our  command.  The  party  left 
Los  Angeles,  on  their  route  northward,  on  the  11th  of  February,  1861, 


110 


GEOLOGY  OF  THE  COAST  RANGES 


and  reached  Monterey  Bay  on  the  15th  of  May;  about  a  fortnight 
was  afterwards  spent  in  that  vicinity,  and  this  was  all  the  time  which 
we  have  been  able  to  give  to  this  extensive  region.  During  the  larger 
part  of  this  exploration  the  party  was  in  charge  of  Professor  Brewer, 
from  whose  notes  the  details  incorporated  in  the  following  section  have 
been  chiefly  drawn. 

The  flrst  thing  which  strikes  the  geologist,  in  examining  the  maps  of 
the  region  in  questiou,  is  the  presence  of  at  least  two  lines  or  systems 
of  upheaval,  which  have  made  themselves  very  manifest  in  the  topo¬ 
graphy;  one  is  the  northwest  and  southeast  system,  with  which  we 
have  already  become  acquainted  in  the  Monte  Diablo  Range,  and  have 
noticed  as  predominating  all  around  the  Bay  of  San  Francisco;  the 
other  is  an  east  and  west  system,  which,  if  it  exists  at  all  in  the  dis¬ 
tricts  described  in  the  preceding  chapters,  has  but  a  very  subordinate 
importance. 

The  region  of  northwest  and  southeast  trends,  in  this  part  of  the  Coast 
Ranges  now  under  examination,  is  especially  that  which  lies  north  of 
San  Luis  Obispo,  and  a  glance  at  the  map  will  show  that  here  the 
main  features  of  the  topography  are  strictly  and  almost  exclusively  de¬ 
pendent  on  this  system  of  upheavals.  The  Salinas  River,  by  far  the 
largest  in  this  portion  of  the  State,  has  a  northwest  course,  and  the 
ranges  of  mountains,  on  either  hand,  are  parallel  with  it  in  their  gene¬ 
ral  direction. 

The  east  and  west  system  is  indicated  at  once  by  the  trend,  in  that 
direction,  of  the  coast  of  Santa  Barbara  Channel,  and  of  the  shore  to 
the  east  of  Point  Duma.  This  east  and  west  coast  line  is  the  expres¬ 
sion  of  a  great  fact  in  the  geology  of  the  country,  which  makes  itself 
perceptible  in  the  topography  far  into  the  interior.  The  main  moun¬ 
tain-ranges  which  have  been  upraised  by  this  system  are  the  Santa  Mo¬ 
nica,  the  Santa  Susanna,  and  the  Santa  Inez,  and  the  trend  of  the  line 
of  islands  on  the  south  side  of  the  Santa  Barbara  Channel  is  strictly  in 
accordance  with  that  of  the  above-named  mountain-chains. 

Between  the  region  of  east  and  west,  and  that  of  northwest  and  south¬ 
east,  trends  is  a  wide  area,  where  the  effects  of  both  these  systems  are 
clearly  perceptible,  the  broken  and  disjointed  ranges,  with  a  very  com¬ 
plicated  topography,  giving  evidence  of  the  interference  of  two  lines  of 


SOUTH  OF  THE  BAY  OF  MONTEREY. 


Ill 


upheaval ;  while  it  is  probable,  from  geological  considerations,  as  will 
be  seen  in  a  future  chapter,  that  one  of  these  systems  is,  in  fact,  to  be 
divided  into  two,  chronologically,  although  the  direction  of  two  is  very 
nearly,  if  not  quite,  coincident.  Of  the  geological  age  of  these  sys¬ 
tems  of  upheaval,  it  will  be  more  convenient  to  speak  in  another  part 
of  this  Report;  an  indication  of  the  names  and  positions  of  the  different 
ranges  included  within  the  area  of  their  influence  is  all  that  will  be  re¬ 
quired,  as  preliminary  to  such  a  sketch  of  the  geological  structure  of  the 
region  as  it  is  in  our  power  to  give. 

The  main  east  and  west  ranges  of  this  district  have  names  of  uni¬ 
versal  recognition ;  they  are  the  Sierra  Santa  Inez,  which  rises  close  to 
the  shore  of  Santa  Barbara  Channel,  the  Sierra  Santa  Monica,  which 
extends  from  the  Cahuenga  Pass  west  to  the  coast  at  Point  Mogu,  and 
the  Sierra  Santa  Susanna,  which  lies  north  of  the  San  Fernando  Valley 
and  the  Semi  Pass  and  River. ' 

The  main  northwest  and  southeast  chains  are  less  unmistakably  de¬ 
signated.  The  name  Sierra  Santa  Lucia  is  that  which  is  best  known 
and  most  frequently  applied  to  what  may  be  called,  with  more  propriety 
than  any  other,  the  dominating  range  of  this  region.  It  extends  in  an 
almost  unbroken  series  of  high  mountain-crests  from  northeast  of  San 
Luis  Obispo  to  Carmelo  Bay,  a  distance  of  nearly  a  hundred  miles. 
From  the  Piedras  Blancas  to  Point  Sur  it  meets  the  Pacific  with  so 
steep  and  rough  a  descent,  that  no  trail,  even,  has  ever  been  carried 
through  along  its  base ;  and  its  lofty  and  precipitous  heights,  covered 
with  chaparral  and  haunted  by  wild  beasts,  are  as  little  traversed  as 
any  portion  of  the  State  of  equal  area.  The  southeastern  continuation 
of  the  Santa  Lucia  chain  is  less  distinctly  marked ;  it  may,  perhaps, 
be  as  well  to  consider  it  as  terminating  at  the  Arroyo  Grande. 

The  eastern  edge  of  the  Santa  Lucia  chain,  consisting  of  a  group  of 
elevations  parallel  with  that  range,  and  separated  from  it  by  the  valleys 
of  the  Carmelo  and  San  Antonio  Rivers,  and  the  tributaries  of  the  Ar¬ 
royo  Seco,  is  locally  known  as  the  Palo  Scrito  Hills  at  its  northern  end, 
and  as  the  San  Antonio  Hills  to  the  southeast  of  the  Soledad  Mission. 
The  whole  chain  is  called,  on  the  Pacific  Railroad  Map,  by  Lieutenant 
Parke,  the  “  Sierra  de  las  Salinas.”  The  range  to  the  east  of  the  Sali¬ 
nas  Valley,  at  its  northern  termination,  where  well-defined  and  lofty,  is 


112 


GEOLOGY  OF  THE  COAST  RANGES 


known  as  the  Gavilan  Range,  and  its  close  connection  on  the  east  with 
the  Monte  Diablo  group,  has  already  been  noticed.  As  continued  to 
the  southeast  of  the  head  of  the  San  Benito,  it  sinks  down  into  a  high, 
rolling  region,  the  various  subdivisions  of  which  are  known  by  the 
same  designations  as  the  streams  and  ranches  in  their  immediate  vici¬ 
nity;  of  these  the  San  Lorenzo  and  the  Estrella  are  the  most  prominent. 

In  the  region  of  short,  broken  ranges,  between  those  just  mentioned 
and  the  distinctly-marked  east  and  west  ones,  the  names  locally  in  use 
are  numerous;  but  as  there  is  no  predominating  chain,  so  there  are  no 
general  terms  for  groups  of  minor  elevations.  The  two  most  promi¬ 
nent  ranges  are,  perhaps,  that  of  the  San  Rafael  Hills,  which  lie  be¬ 
tween  the  Santa  Inez  and  Santa  Maria  Rivers,  and  the  Cuyamas  Range, 
which  runs  between  the  last-named  river  and  the  Cuyamas.  The  direc¬ 
tion  of  these  chains,  which  are  nearly  parallel,  so  far  as  we  have  been 
able  to  ascertain  is  about  U.  60°  W.  One  or  both  of  them  may,  per¬ 
haps,  be  considered  as  the  prolongation  of  the  Santa  Lucia  chain. 
This  direction  of  N.  60°  to  65°  W.,  is  also  that  of  the  line  of  upheavals 
which  marks  the  northeastern  limit  of  the  Coast  Ranges,  along  the  line 
of  the  desert,  southwest  of  the  Canada  de  las  Uvas  and  the  ridges 
which  unite  the  Sierra  and  Coast  chains  of  mountains  together. 

The  whole  region  embraced  in  and  between  the  above  ranges  of  hills 
and  mountains  is  essentially  of  one  character.  It  is  sparsely  inhabited 
and  generally  very  poorly  supplied  with  water.  Such  favored  districts 
as  can  be  irrigated  are  fertile  in  the  highest  degree,  and  may  be  adapted 
to  almost  any  semitropical  culture.  The  most  attractive  localities  were 
selected  by  the  monks  of  the  Franciscan  order  for  the  missions  which 
they  began  to  establish,  throughout  this  portion  of  Upper  California, 
in  1769.  Of  these,  no  less  than  eleven  were  included  within  the  limits 
of  the  region  between  San  Fernando  Yalley  and  Monterey.  These 
were  the  Missions  of  San  Fernando,  San  Buenaventura,  Santa  Bar¬ 
bara,  La  Purisima  Concepcion,  Santa  Inez,  San  Luis  Obispo,  San  Mi¬ 
guel,  San  Antonio,  La  Soledad,  Carmelo,  and  San  Juan  Bautista.  The 
situation  of  most  of  these  were  admirably  selected,  and  the  ruined  and 

deserted  buildings  are  still  prominent  and  picturesque  objects.* 

• 

*  For  a  full  account  of  the  foundation  of  these  missions,  and  of  their  condition  twenty- 
live  years  ago,  see  Duflot  de  Mofras,  “Exploration  de  1 ’Oregon,  des  Californies,  &c.,” 
Paris,  1844. 


SOUTH  OF  THE  BAY  OF  MONTEREY. 


113 


If  the  valleys  throughout  this  region  are  dry,  the  mountains  are  still 
more  so;  they  are  usually  covered  more  or  less  with  chaparral,  which 
effectually  keeps  off  intruders.  In  the  vicinity  of  the  Ocean,  and,  es¬ 
pecially,  near  the  summits  of  the  higher  mountain-ranges  and  in  the 
deep  and  shaded  canons  on  their  sides,  where  the  moisture  brought  in 
by  the  winds  from  the  sea  is  not  too  rapidly^evaporated,  there  is  a  con¬ 
siderable  growth  of  forest  trees ;  the  number  of  these  increases  as  we 
go  towards  the  northwest.  Pines  and  oaks  greatly  predominate  in 
number  over  the  other  genera.  Of  the  pines,  Pinus  Coulteri ,  P.  insig- 
nis ,  and  P.  monticola  are  the  most  characteristic  species ;  of  the  oaks, 
Quereus  lobata  (called  also  Q.  Hindsii ),  Q.  Douglasii ,  Q.  Garry  ana,  Q.  agri- 
folia ,  Q.  Sonomensis  (synonyms,  Q.  California ,  Q.  tine  tor  ia,  and  Q.  Kel- 
loggii)  are  the  most  abundant.  Of  the  cedars,  the  redwood,  Sequoia 
sempervirens ,  is  found  in  limited  patches  near  the  sea,  from  Point  Con¬ 
cepcion  north ;  the  Cupressus  macrocarpa  (Monterey  cedar)  is  a  magnifi¬ 
cent  tree,  resembling  the  cedar  of  Lebanon,  but  very  restricted  in  its 
range.  Of  other  prominent  trees,  which  give  a  character  to  the  scenery 
of  this  part  of  the  Coast  Ranges,  the  following  may  be  mentioned : 
Tetranthera  California  (laurel  or  bay),  Arbutus  Menziesii  (madrona),  a 
characteristic  and  beautiful  tree,  Populus  monilifera  (cottonwood),  flour¬ 
ishing  everywhere  in  the  Coast  Ranges,  in  the  valleys  along  the  sides 
of  the  streams,  Platanus  racemosus  (sycamore),  growing  chiefly  along 
the  river  banks.  Of  the  shrubs,  Adenostema  faseicidata  (chamiso),  Arcto- 
staphylos  glauea  (manzanita),  and  the  Ceanothus ,  called  “  wild  lilac”  by 
settlers  from  the  Eastern  States,  on  account  of  the  resemblance  of  the 
delightful  perfume  of  its  flowers  to  that  of  the  common  lilac,  are  the 
most  abundant  and  prominent.  Mingled  together,  and  associated  with 
a  variety  of  species  of  shrubby  oaks,  each  furnished  with  as  many 
thorns  as  there  are  points  to  leaves  or  branches,  this  vegetation  makes 
up  that  horrible  undergrowth,  with  which  we  have  become  intimately 
acquainted,  on  almost  every  mountain  slope  from  San  Diego  to  Sis- 
kyou,  to  the  great  detriment  of  skins,  clothes,  and  tempers.* 

Almost  all  the  really  valuable  land  in  this  part  of  the  Coast  Ranges 

*  For  a  complete  account  of  the  distribution  of  trees  and  shrubs  throughout  the  State, 
see  the  volume  of  Physical  Geography,  in  the  series  of  the  Final  Report. 

GEO L.  VOL.  T.  — 15 


114 


GEOLOGY  OF  THE  COAST  RANGES 


A 


is  occupied  by  Spanish  grants,  or  ranches,  some  of  which  are  of  im¬ 
mense  size,  containing  from  forty  to  fifty  thousand  acres ;  these  are 
located  along  the  valleys  of  nearly  all  the  principal  streams,  and  although 
these  ranch-grants  do  not  probably  cover  more  than  one-eighth  of  the 
surface,  yet  the  owner  of  the  valley  has,  in  point  of  fact,  undisturbed 
possession  of  the  adjacent  mountains.  The  raising  of  cattle  was,  in 
former  times,  almost  the  exclusive  business  of  the  rancheros;  but,  of 
late  years,  sheep-growing  and  the  cultivation  of  the  vine  have  been  of 
rapidly  increasing  importance. 

There  are  no  mines  of  any  value  in  this  part  of  the  Coast  Ranges, 
so  far  as  is  yet  known;  nor  has  the  result  of  our  explorations  been  such 
as  to  lead  to  the  belief  that  this  will  ever  become  a  mining  region. 
Cinnabar  is  the  ore  which  is  most  likely  to  be  found  in  deposits  of  suffi¬ 
cient  extent  to  be  valuable,  in  the  region  of  the  metamorpliic  Cretace¬ 
ous,  Within  a  short  time,  this  ore  is  reported  to  have  been  discovered 
in  the  Tertiary  strata,  not  far  from  San  Luis  Obispo,  but  the  locality 
has  not  been  examined  by  any  of  our  corps.  Small  quantities  of  ar¬ 
gentiferous  galena,  found  on  the  Alisal  Ranch,  a  few  miles  northeast  of 
Monterey,  have  given  rise  to  stories  of  silver  mines  of  great  richness, 
which  have  beeui  handed  down  from  author  to  author,  and  have  led  to 
much  exploration,  but  always  without  success.  The  broken  and  semi- 
metamorphosed  condition  of  the  rocks,  through  this  region,  as  also 
their  recent  geological  age,  renders  it  improbable  that  veins  or  depo¬ 
sits  of  valuable  metalliferous  ores  (with  the  exception  of  those  of  quick¬ 
silver)  will  be  found  here  with  sufficient  development  to  be  capable  of 
being  continuously  and  permanently  worked.  Chromic  iron  may,  how¬ 
ever,  be  discovered,  sufficiently  near  to  a  place  of  shipment  to  become 
of  value  in  time.  The  deposits  of  asphaltum,  on  and  near  the  coast, 
are  well  known,  and  all  such  as  have  been  visited  by  our  corps  will  be 
found  described  in  this  chapter.  These  are  very  extensive  and  have 
been  utilized  to  a  considerable  extent,  for  some  years  past,  for  local 
consumption,  the  material  being  much  used  for  covering  the  roofs  of 
houses  in  the  vicinity  of  the  deposits.  The  asphaltum  has  also  been 
shipped  to  San  Francisco  and  used  for  roofs  and  pavements,  and  the 
business  has  been  profitable  in  a  small  way. 

Within  the  last  year  the  u  oil-excitement”  of  the  Atlantic  States  has 

1/ 


SOUTH  OF  THE  BAY  OF  MONTEREY. 


115 


penetrated  to  the  Pacific  coast,  and  the  presence  of  a  small  proportion  of 
a  more  fluid  oil,  in  connection  with  the  solid  asphaltum,  has  led  to  un¬ 
bounded  hopes  of  a  vast  production  of  petroleum  in  the  Coast  Ranges 
of  California,  creating  an  excitement  which  has  been  skilfully  made 
use  of  by  unprincipled  speculators,  for  their  own  purposes,  by  the  crea¬ 
tion  of  stock  companies  with  an  immense  number  of  shares,  which 
have  been  disposed  of  to  a  credulous  public,  nearly  the  whole  proceeds 
of  their  sale  being  clear  profit  to  the  promoters  of  these  enterprises, 
while  it  is  certain  that,  even  under  the  most  favorable  conditions,  the 
luckless  stockholders  will  never  receive  even  a  moderate  return  for  the 
money  invested. 

Our  line  of  exploration,  through  the  asphaltum  region  in  Santa  Bar¬ 
bara  and  Los  Angeles  Counties,  did  not  happen  to  lead  us  to  those 
ranches  which  have  become  celebrated  by  the  formation  of  monster  oil 
companies  on  them,  although  we  examined  carefully  all  the  localities 
where,  at  that  time,  the  asphaltum  was  being  made  practically  avail¬ 
able  ;  in  none  of  these  did  it  happen  that  more  than  a  trace  of  a  really 
fluid  oil  could  be  seen.  In  forming  an  opinion  of  the  probable  truth 
of  recently  published  statements  of  the  occurrence  of  vast  quantities  of 
liquid  petroleum  in  this  region,  we  have  relied  to  some  extent  on  the 
observations  of  Dr.  Antisell,  one  of  the  geologists  to  the  Pacific  Rail¬ 
road  Survey,  and  the  author  of  a  work  on  “  Photogenic  Oils,”  who  vis¬ 
ited  all  the  known  localities  of  asphaltum  and  bituminous  substances 
in  the  counties  of  Santa  Barbara  and  Los  Angeles,  and  whose  observa¬ 
tions  have  the  merit  of  being  entirely  disinterested.  The  examination 
of  his  chapter  “  On  Bituminous  Effusions,”  in  Volume  VII  of  the  Pacific 
Railroad  Report,  and  the  comparison  of  his  accounts  with  those  which 
have  since  been  given  by  interested  parties,  will  serve  to  convince  every 
unprejudiced  person  that  these  latter  have  not  been  distinguished  for  a 
strict  adherence  to  truth — to  use  a  mild  form  of  expression  for  a  very 
ugly  fact. 

At  an  early  period  of  the  Survey,  a  considerable  quantity  of  the  as¬ 
phaltum  of  this  region  was  forwarded  by  us  to  an  Eastern  city,  where  it 
was  examined  by  a  highly  skilful  chemist,  well  acquainted  with  this 
class  of  substances,  to  see  if  it  could  be  made  available  as  a  source  of 
burning  oil,  under  the  present  conditions.  The  answer  to  this  question 


lie 


GEOLOGY  OF  THE  COAST  RANGES 


was  in  the  negative,  and  subsequent  trials,  on  a  somewhat  larger  scale, 
in  California,  have  confirmed  this  result.  We  consider  it  a  settled  ques¬ 
tion,  that  with  the  facilities  and  conditions  which  now  exist,  the  asphal- 
tum  cannot  he  profitably  used  for  the  manufacture  of  burning  or  lubri¬ 
cating  oil.  It  is  not  necessary,  in  this  place,  to  go  into  a  detailed 
statement  of  facts  to  prove  this ;  that  may  be  more  properly  reserved 
for  the  volume  of  Economical  Geology.  Those  who  doubt  the  state¬ 
ment  can,  if  they  see  fit,  devote  their  time  and  money  to  proving  it  to 
be  incorrect  by  actual  practical  results. 

The  next  question  which  arises  in  this  connection  is,  whether  a  fluid 
oil  exists  on  the  surface  in  sufficient  quantity  to  pay  for  collecting  in 
the  large  way.  It  has  been  stated,  in  the  published  prospectuses  of 
some  of  the  California  oil  companies,  that  rivers  of  oil  were  flowing 
through  the  ranches  of  which  they  were  the  lucky  proprietors,  which 
only  required  to  be  conducted  down  to  the  sea-shore  in  pipes,  or  canals, 
to  furnish  for  shipment  a  boundless  supply  of  material.  It  seems  hardly 
possible  that  anybody  should  be  found  sufficiently  credulous  to  be  im¬ 
posed  on  by  these  statements.  Apart  from  Dr.  Antisell’s  descriptions, 
which  show  most  clearly  that  the  thinner  tarry  material,  as  it  oozes 
from  the  rocks,  everywhere  soon  hardens  into  asphaltum,  it  is  evident 
from  the  operations  of  those  who  have,  in  years  gone  by,  endeavored  to 
distill  oil  from  the  material  obtainable  here,  that  no  great  quantity  of  a 
fluid  material  could  be  secured,  as  they  used  the  solid  asphaltum,  or  the 
sand  impregnated  with  it,  for  distillation,  and,  as  it  need  hardly  be  added, 
without  being  successful  pecuniarily.  Besides,  the  fact  that  the  com¬ 
pany  in  whose  prospectus  conduits  and  canals  to  convey  off*  the  liquid 
oil  figure  most  conspicuously,  actually  commenced  operations  by  boring 
(if  any  credence  can  be  given  to  the  statements  of  the  newspapers  on 
this  point),  is  sufficient  evidence  that  the  originators  of  these  schemes 
knew  that  they  were  deceiving,  when  they  put  forth  their  advertise¬ 
ments  and  pamphlets. 

The  question  resolves  itself,  then,  into  this :  Is  it  probable  that  flow¬ 
ing  wells  will  be  struck  by  boring,  as  in  the  oil  region  of  Pennsylvania, 
and  that  these  will  deliver  a  liquid  oil,  or  petroleum,  in  sufficient  quan¬ 
tity  to  make  it  worth  while  to  take  up  the  business  and  carry  it  on,  in 
the  large  way?  We  say  “  in  the  large  way,”  because  it  is  self-evident 


SOUTH  OF  THE  BAY  OF  MONTEREY. 


117 


that,  to  pay  dividends  to  incorporated  stock  companies  with  heavy  no¬ 
minal  capitals,  the  business  must  be  done  on  a  large  scale.  A  delivery 
of  a  few  barrels  a  day  would  not  amount  to  enough  to  pay  the  rent  of 
the  office  of  the  company  in  New  York  or  Philadelphia,  much  less  the 
salaries  of  the  office-holders.  A  few  lines  will  be  devoted  to  answering 
the  question,  whether  the  geological  structure  and  conditions  in  the 
Coast  Ranges  south  of  San  Francisco  Bay  are  such  as  to  justify  a  large 
expenditure  of  money  in  the  expectation  of  striking  copiously-flowing 
wells  by  boring  to  a  considerable  depth. 

The  great  bituminous  slate  formation,  of  Tertiary  age,  extends  through 
California,  from  Los  Angeles  as  far  north  as  Cape  Mendocino.  No 
doubt  it  contains  bituminous  matter  enough  to  supply  the  world  for  an 
indefinite  period,  could  this  be  made  available  without  expense.  But 
it  will  be  observed  that  the  strata  of  this  formation,  all  through  the  re¬ 
gion  south  of  the  Bay  of  San  Francisco,  are  turned  up  at  a  high  angle, 
in  this  respect  occupying  a  very  different  position  from  the  oil-produc¬ 
ing  beds  in  the  Eastern  States.  There,  the  strata  in  which  petroleum  is 
found  in  abundance,  and  in  which  all  the  wells  which  yield  any  consi¬ 
derable  quantity  of  this  material  are  sunk,  are  horizontal  or  inclined  at 
a  very  moderate  angle.  Nowhere  is  oil  obtained  in  large  quantity, 
where  the  stratum  in  which  it  originates  is  exposed  to  the  air  by  being 
turned  up  on  edge,  or  is  only  covered  by  light  and  porous  accumulations 
of  detritus.  The  reason  of  this  is  very  evident :  the  oil  is  slowly  ela¬ 
borated  or  brought  together  in  a  certain  bed,  or  set  of  beds;  and,  unless 
confined  in  some  way,  so  that  it  cannot  escape,  it  must  be  forced  to  the 
surface  by  capillary  attraction,  hydrostatic  pressure,  or  that  of  gas  gene¬ 
rated  at  the  same  time,  when  it  escapes  and  is  lost;  to  allow  it  to  accu¬ 
mulate,  there  must  be  an  impervious  covering  of  rock  over  the  oil- 
stratum  proper,  which  will  confine  the  fluid  material  within  limits,  and 
allow  it  to  accumulate,  away  from  the  influence  of  the  air.  For  this 
reason,  a  large  flow  of  oil  on  the  surface  cannot  be  considered  as  a  favor¬ 
able  indication  for  boring  wells,  and  much  less  can  heavy  accumula¬ 
tions  of  asphaltum  be  so  regarded.  If,  then,  flowing  wells  are  struck 
in  California,  it  is  more  likely  to  be  in  those  portions  of  the  region 
north  of  the  Bay  of  San  Francisco,  where  the  bituminous  slates  are  less 
disturbed,  and  not  set  up  on  edge,  and  where  they  may  perhaps  be  cov- 


118 


GEOLOGY  OF  THE  COAST  RANGES 


ered  by  formations  of  later  age,  wKicli  will  act  as  covers  and  recepta¬ 
cles  for  the  elaborated  oil.  In  the  Coast  Ranges  south  of  the  Bay  of 
Monterey,  as  the  bituminous  shales  are  everywhere  turned  up  on  edge 
and  have  no  cover  of  impervious  rock,  the  inference  is  unavoidable,  that 
flowing  wells,  or  at  least  those  delivering  any  considerable  quantity  of 
liquid  petroleum,  cannot  be  expected  to  be  got,  by  boring  to  any  depth; 
the  probabilities,  at  least,  are  decidedly  against  it.  While,  therefore,  we 
would  not  object  to  a  reasonable  and  prudent  expenditure  of  small 
amounts  to  test  the  question  whether  fluid  oil  can  be  obtained  in  Cali¬ 
fornia  in  sufficient  quantity  to  pay  a  moderate  profit  on  a  bond  fide  in¬ 
vestment,  we  would  caution  all  against  paying  to  speculators  an  im¬ 
mense  premium  for  the  privilege  of  making  these  experiments  on  lands 
which  they  have  secured  for  a  small  sum,  and  where  there  are  no  better, 
if  as  good,  chances  of  success  as  on  many  other  tracts  which  have  not 
yet  fallen  into  the  hands  of  these  monster  stock  companies. 

Whether  the  asphaltum  of  California  is  derived  from  the  thickening, 
or  oxidation,  by  exposure  to  the  atmosphere,  of  exactly  the  same  sub¬ 
stance,  chemically  speaking,  as  that  which  is  called  petroleum  in  Penn¬ 
sylvania,  is  a  matter  for  chemical  investigation.  In  the  light  of  the 
facts  and  considerations  just  presented,  it  does  not  appear  to  be  eco¬ 
nomically  important  that  it  should  be  settled  at  once.  How  large  a 
portion  of  the  numerous  hydrocarbons  which  are  originally  contained 
in  the  bituminous  slates  of  California  evaporate  on  exposure,  and  how 
many  of  them  become  oxidized  into  asphaltum,  is  a  delicate  subject  for 
investigation.  From  the  well-known  fact  that  there  are  few,  if  any, 
deposits  of  asphaltum  or  asphaltic  material  existing  on  the  surface  in 
the  oil  region  of  Pennsylvania,  although  the  oil  itself  appears  to  have 
been  escaping  at  numerous  points  for  an  indefinite  period  of  time,  it 
appears  to  be  probable,  at  least,  that  the  original  chemical  constitution 
of  the  mass  of  bituminous  matter  in  the  oil-bearing  shales  of  Palaeo¬ 
zoic  age  is  different  from  that  material  which  occurs  in  the  Tertiary 
rocks  of  California,  and  of  which  at  least  much  the  largest  part  does, 
on  exposure,  become  consolidated  into  a  hard  and  brittle  material, 
which  certainly  no  longer  contains  more  than  a  very  small  percent¬ 
age  of  light  oil. 

In  view  of  the  above  facts,  it  will  not  be  necessary  to  discuss  the 


SOUTH  OF  THE  BAY  OF  MONTEREY. 


119 


question  how  far  the  greatly  increased  expenses  of  obtaining  and  work¬ 
ing  machinery,  of  barrels,  of  transportation,  and  of  labor,  would  render 
it  difficult  for  California  oil-wells,  if  any  did  exist,  to  compete  with 
those  in  the  Eastern  States,  where  the  conditions  are  so  much  more 
favorable  in  these  respects. 

Many  facts  will  be  presented  in  this  chapter  which  have  come  under 
our  own  observation,  in  regard  to  the  occurrence  of  asphaltum  in  the 
region  in  question,  and  from  these  some  aid  may  be  obtained  in  form¬ 
ing  an  opinion  as  to  the  correctness  of  the  statements  which  have  been 
made  in  these  few  preliminary  remarks. 

We  proceed  now  to  the  consideration  of  the  geological  structure  of  the 
Coast  Ranges  north  of  Santa  Barbara,  commencing  with  the  San  Fer¬ 
nando  Valley  and  the  Sierra  Santa  Susanna,  and  proceeding  northward, 
as  being  the  more  convenient  way-of  giving  our  observations,  which 
were  taken  in  that  order.  The  Santa  Monica  Range  will  be  included 
in  the  next  section,  or  that  devoted  to  the  Coast  Ranges  south  of  Santa 
Barbara  Channel,  as  being  closely  connected  with  the  San  Gabriel 
Range,  and  therefore  more  conveniently  taken  up  at  the  same  time 
with  that. 


Section  II. — The  Region  from  San  Fernando  Valley  north  to  the 

Bay  of  Monterey. 

This  valley,  or  plain,  occupies  the  depression  between  the  Santa 
Susanna  chain  on  the  north,  the  Santa  Monica  on  the  south,  the  San 
Gabriel  on  the  east,  and  the  low  ridges  and  hills  running  transversely 
between  the  Santa  Susanna  and  the  Santa  Monica  on  the  west.  It  is 
about  twenty  miles  long  and  twelve  miles  wide,  and  is  drained  towards 
the  south  by  the  Los  Angeles  River.  The  soil  of  most  of  the  plain 
is  sandy,  and  the  streams  running  into  the  valley  from  various  direc¬ 
tions  sink  when  they  strike  it,  and  do  not  flow  on  the  surface,  except 
during  seasons  of  heavy  and  long-continued  rains.  A  warm  spring 
occurs  on  the  south  side  of  the  plain,  at  the  base  of  the  Santa  Monica, 
on  the  Encino  Ranch.  The  water  had,  in  February,  1861,  a  tempera¬ 
ture  of  88°,  and  a  slightly  alkaline  taste,  and  appeared  to  contain  car- 


120 


GEOLOGY  OF  TIIE  COAST  RANGES 


bonate  of  soda  and  the  sulphates  of  soda  and  magnesia,  in  so  consider¬ 
able  a  quantity  as  to  he  unfit  for  irrigation. 

The  Sierra  Santa  Susanna  lies  on  the  north  side  of  this  plain,  and 
extends  west  as  far  as  the  valley  of  Santa  Clara ;  this  range  is  also  fami¬ 
liarly  known  as  the  “  Scorpion  Hills.”  From  the  plain,  the  hills  to  the 
north  present  a  hold  and  precipitous  front,  as  the  strata  of  which  they 
are  made  up  are  heavy-bedded  sandstones,  dipping  to  the  north,  and 
presenting  their  broken  edges,  in  the  form  of  high  cliffs  of  nearly 
naked  rock,  to  the  south ;  these  cliffs  rise  in  bold  escarpments,  so  that 
their  stratification  is  distinctly  visible  from  a  great  distance,  and  from 
the  very  massive  character  of  the  strata,  their  position  is  much  easier 
made  out  by  an  observer  several  miles  off*,  than  by  one  on  the  spot. 
The  material  is  coarse,  often  passing  into  conglomerates,  and  generally 
red  in  color;  it  has  a  marked  tendency  to  weather  into  fantastic  forms, 
the  angular  masses  becoming  rounded  in  outline  by  the  disintegration 
of  the  rock,  and  having  many  irregular  cavities  worn  in  it ;  detached 
fragments,  originally  angular,  finally  assume,  under  the  influence  of 
the  weather,  the  appearance  of  enormous  boulders.  To  the  northwest 
of  our  camp  at  the  base  of  Scorpion  Hills  (Camp  No.  14),  the  sandstone 
in  the  higher  ridges  had  a  strike  of  S.  46°  W.,  with  a  dip  to  the  north 
of  from  20°  to  30°;  the  highest  of  these  ridges  rise  from  1800  to  1900 
feet  above  the  plain,  or  about  3000  feet  above  the  sea.  Along  the  foot 
of  the  range,  west  of  Camp  14,  were  several  hills  near  the  base  of  the 
main  range,  but  isolated  from  it.  Those  near  camp  were  of  sandstone 
with  highly  inclined,  sometimes  vertical,  strata;  farther  west,  along  the 
western  edge  of  the  valley,  they  were  found  to  be  of  bituminous  slate. 
Three  or  four  miles  west  of  the  Scorpion  Ranch,  there  is  a  stratum  of 
white,  crystalline  limestone  running  through  the  foot-hills,  and  rising 
in  sharp  steep  hills  to  the  height  of  300  to  400  feet.  This  limestone  is 
burned  in  the  vicinity  and  appears  to  make  good  lime. 

The  annexed  section  from  the  Santa  Monica  Range,  in  a  northwest¬ 
erly  direction  across  the  San  Fernando  Plain,  to  the  summit  of  the 
Santa  Susanna  Range,  a  distance  of  about  forty  miles,  shows  the  posi¬ 
tion  of  the  rock  in  this  region ;  but  only  in  an  approximative  way,  as 
far  as  the  Santa  Susanna  Range  is  concerned,  since  no  minutely-detailed 
examination  was  made. 


SOUTH  OF  THE  BAY  OF  MONTEREY. 


121 


The  structure  of  the  Santa  Monica 
Range  has  already  been  described,  and 
nothing  farther  need  be  added  here. 
There  is  no  doubt  that  the  sandstones 
of  the  Santa  Susanna  Range  are  of  the 
same  age  as  those  of  the  Santa  Mo¬ 
nica,  namely,  Miocene,  at  least  in  con¬ 
siderable  part.  A  series  of  beds  of 
later  age,  referred  by  Mr.  Gabb  to  the 
Pliocene,  was  discovered  by  Baron 
Richthofen  to  the  north  of  the  east 
end  of  the  San  Fernando  Plain ;  but 
we  have  not  the  exact  position  of  the 
locality,  nor  are  the  relations  of  the 
strata  to  those  exhibited  in  the  section 
above  known. 

The  section  shows  that  there  is  evi- 
dently  an  immense  fault  or  break  in 
the  strata  at  the  southern  base  of  the 
Santa  Susanna  Range,  by  which  the 
rocks  to  the  north  have  been  uplifted 
at  least  3000  feet,  and  perhaps  much 
more.  To  the  north,  the  Santa  Clara 
Valley  appears  to  occupy  the  bottom 
of  a  synclinal  curve,  but  the  range  to 
the  north  of  that  stream  is  but  little 
known ;  it  is  possible  that  the  strata 
there  may  be  horizontal,  and  resting 
unconformably  on  the  rocks  below, 
and  that  they  are  the  Pliocene  beds 
noticed  above. 

At  the  western  end  of  the  San  Fer¬ 
nando  Valley,  among  the  rounded 
foot-hills  which  connect  the  Santa  Su¬ 
sanna  and  Santa  Monica  Ranges,  there 
is  some  coarse  conglomerate,  probably 

OTCOL.  VOL.  T. — 10 


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122 


GEOLOGY  OF  THE  COAST  RANGES 


of  later  Pliocene  age,  like  that  on  the  south  side  of  the  last-named 
range.  In  this  region  the  strata  are  exceedingly  broken,  having  a  gen¬ 
eral  northeast  and  southwest  strike,  and  a  dip  at  every  possible  angle 
intermediate  between  southeast  and  northwest,  and  varying  in  amount 
from  20°  to  70°.  In  some  places  the  strata  are  bent  into  immense 
arches ;  but  usually  the  force  of  the  upheaval  has  broken  them  oft  ab¬ 
ruptly,  and  they  are  now  left  in  a  condition  of  indescribable  confusion, 
jammed  together  and  piled  up  into  a  labyrinth  of  hills  and  canons. 
Portions  of  these  sandstones  are  here  well  filled  with  fossils,  ot  Miocene 
age,  but  they  are  in  a  very  poor  state  of  preservation,  from  the  coarse, 
friable  character  of  the  rock  in  which  they  are  imbedded.  The  strata 
containing  these  fossils  most  abundantly  formed  a  high  ridge,  with  a 
strike  of  N.  64°  E.,  and  a  dip  of  20°  to  the  southeast,  the  northern 
slope  being  very  steep  and  rough.  These  strata  were  covered  on  the 
east  side  by  conglomerates,  destitute  of  fossils,  which  were  made  up  of 
pebbles  of  jasper,  quartz,  and  other  rocks  similar  to  those  seen  by  us  in 
the  Santa  Anna  Range. 

Still  farther  to  the  north  and  northeast,  high  hills  rise,  which  com¬ 
mand  an  extensive  view  of  the  bituminous  slates  and  fine-grained 
sandstones  to  the  northwest.  The  height  of  this  ridge,  above  our  camp 
on  the  edge  of  the  San  Fernando  Plain,  was  2735  feet,  or  3950  feet 
above  the  sea. 

The  ridges  bounding  the  San  Fernando  Valley  on  the  southwest  are 
made  up  of  light-colored  bituminous  slates,  dipping  generally  to  the 
east  or  northeast ;  they  form  rounded  hills,  bearing  the  marks  of  ex¬ 
tensive  erosion.  A  higher  ran^e  to  the  west  of  these  hills  connects  the 
two  chains,  and  rises  to  a  height  of  3000  feet  above  the  sea,  being  made 
up  of  Miocene  sandstones,  highly  inclined  and  in  some  places  meta¬ 
morphosed.  Between  the  lower  rounded  hills  of  slate  and  the  high 
sandstone  ridge,  there  is  a  series  of  valleys  in  which  are  the  Virgenes, 
Triunfo,  and  other  ranches.  The  Virgenes  Creek  breaks  through  the 
Santa  Monica  Range  and  runs  south,  emptying  into  the  sea  a  little 
east  of  Point  Duma. 

Five  or  six  miles  southeast  of  the  Triunfo  Ranch  (Camp  15),  rise  the 
high  sandstone  ridges  of  the  Santa  Monica.  These  were  examined  to 
the  east  of  Virgenes  Creek,  where  they  have  a  strike  of  S.  24°  W.  to 


SOUTH  OF  THE  BAY  OF  MONTEREY. 


123 


S.  49°  W.,  and  dip  to  the  north  at  an  angle  of  from  40°  to  70°,  the 
strata  presenting  their  broken  edges  to  the  east  and  southeast  in  steep 
precipices.  These  ridges  are  extremely  rough  and  rocky,  as  may  be 
seen  in  the  annexed  section  (Fig.  8). 


Fig.  8. 

Section  near  Triunfo  Eanch. 


c  b  a  a 

a,  a.  Sandstone,  b.  Metamorphic  hills,  e.  Valley  of  Virgenes  Creek. 


Extending  along  the  base  of  these  ridges  of  very  slightly  metamor¬ 
phosed  sandstone,  which  rise  to  the  height  of  2000  feet*  there  is  a  low 
range  of  sharp  ridges,  from  400  to  600  feet  high,  of  which  the  strata 
have  the  same  dip  and  strike  as  those  in  the  higher  mountains  south, 
but  which  are  highly  metamorphosed,  and  perhaps  intrusive,  although 
no  rock  was  seen  which  could  be  recognized  as  positively  eruptive. 
Some  portions  of  these  low  ridges  were  of  a  dark,  compact*  or  semi- 
crystalline  rock,  apparently  diorite ;  others  were  amygdaloidal,  having 
the  cavities  tilled  with  carbonate  of  lime,  and  disintegrating  rapidly, 
forming  a  dark,  reddish-brown  soil.  Some  traces  of  metamorphism 
were  observed  in  the  higher  ridge  of  sandstones,  the  granite  coming  to 
the  surface  in  one  place,  as  it  does  farther  east  in  the  range  on  an  ex¬ 
tensive  scale. 

Between  the  Triunfo  and  Cayeguas  Ranches  several  low  sandstone 
ridges  were  crossed,  and  about  six  miles  north  of  Triunfo,  a  very  steep 
one,  also  of  sandstone,  having  an  east  and  west  direction  and  a  north- 
.  erly  dip,  the  strata  being  much  metamorphosed  at  the  base  of  the  ridge 
on  the  southern  side.  This  ridge  was  examined,  in  its  western  continu¬ 
ation,  from  our  camp  at  the  Cayeguas  Ranch  (Camp  16),  where  it  was 
found  to  rise  to  the  height  of  1000  or  1100  feet  above  the  valley,  com¬ 
manding  a  good  view  of  higher  and  rougher  ridges,  apparently  of  the 
same  sandstone,  lying  off  to  the  south  and  southwest,  the  strata  in 
some  places  appearing  quite  vertical.  Where  examined,  these  strata 


124 


GEOLOGY  OF  THE  COAST  RANGES 


were  found  to  be  extensively  metamorphosed,  so  that  it  was  not  easy 
to  decide  whether  they  were  accompanied  by  intrusive  or  eruptive  rock. 
From  Professor  Brewer’s  notes,  however,  it  appears  that  he  inclines  to 
the  belief  that  the  amygdaloidal  rock  seen  by  him,  and  which  had  so 
trappean  an  appearance,  was  in  reality  a  metamorphic  sandstone.  The 
strata  in  this  region  have  a  general  east  and  west  direction,  and  dip  to 
the  north  at  an  anode  of  from  30°  to  45°.  On  the  hills  north  of  the 
Cayeguas  Ranch  there  are  beds  of  light-colored  sandstones,  containing 
considerable  numbers  of  Pliocene  fossils.  These  hills,  at  a  point  a  mile 
and  a  half  north  of  the  ranch,  were  found  to  be  from  600  to  700  feet 
high  above  the  valley;  here  the  ridge  runs  east  and  west  and  the  strata 
dip  to  the  north,  having  the  Cayeguas  Valley  on  the  south,  and  Las 
Posas  on  the  north.  The  topography  of  the  region  is  very  complicated, 
and  could  hardly  be  represented  at  all  except  on  a  map  on  a  large  scale. 
The  ridge  near  which  the  best  fossils  were  obtained  is  furrowed  by 
canons,  with  exceedingly  steep  sides;  namely  from  40°  to  60°,  as  mea¬ 
sured  by  the  clinometer.  All  through  here  the  strata  bear  the  marks 
of  great  disturbance  and  of  extensive  metamorphic  agencies  at  work 
below,  although  the  presence  of  volcanic  or  trappean  rock  on  the  sur¬ 
face  seems  not  to  have  been  settled  beyond  a  doubt.  At  all  events, 
the  metamorphosed  strata,  if  such  they  were,  occupied  a  position  confor¬ 
mable  in  dip  and  strike  with  the  beds  in  which  they  were  intercalated. 
Some  of  these  altered  beds  were  very  friable,  decomposing  readily 
into  a  dark-brown  soil,  very  different  from  that  produced  by  the  disin¬ 
tegration  of  the  ordinary  sandstones.  Of  these  latter,  some  were  made 
up  of  coarse,  clean,  white  beach-sand,  closely  compacted  together  and 
containing  numerous  fragments  of  shells,  broken  and  water-worn. 
Some  of  the  strata  were  very  fossiliferous,  many  species  being  repre¬ 
sented  ;  but  they  were  in  such  a  frail  condition  that  but  few  good  speci¬ 
mens  were  collected.  Many  fragments  of  sea- weeds  and  a  vertebra  of 
a  fish  were  also  noticed,  as  well  as  some  remains  of  corals.  These 
beds  are  considered  by  Mr.  Gabb  as  being  of  Pliocene  age,  as  will  be 
seen  in  another  part  of  this  Report. 

The  San  Buenaventura,  or  Santa  Clara  Plain,  as  it  is  called  on  the 
Pacific  Railroad  Map,  forms  a  triangular  area  inclosed  between  the 
Santa  Susanna,  Santa  Monica,  and  the  transverse  connecting  range 


SOUTH  OF  THE  BAY  OF  MONTEREY. 


125 


noticed  above  on  the  east,  the  San  Buenaventura  hills  on  the  north, 
and  the  Ocean  on  the  southwest.  All  the  water  seen  on  the  plain  was 
alkaline,  except  that  of  the  Santa  Clara  River.  Hills  of  the  white  bi¬ 
tuminous  slate  lie  to  the  northeast  of  this  plain,  in  which  the  strata,  as 
indicated  in  numerous  exposures,  dip  to  the  southwest,  or  south-south¬ 
west.  These  hills  approach  the  sea  at  the  Mission.  To  the  east  and 
northeast,  at  some  distance  in  the  interior,  were  high  mountains,  snow- 
covered  on  their  summits  at  the  season  of  our  visit  (March,  1861),  and 
apparently  5000  or  6000  feet  above  the  sea ;  in  these  the  strata  of  bitu¬ 
minous  slate  were  very  conspicuous  from  a  distance,  evidently  dipping 
to  the  south  and  southwest,  and  presenting  their  broken  edges  to  the 
south.  The  soil  derived  from  the  decomposition  of  these  slates,  where 
seen  in  the  plain  or  on  the  low  hills,  was  of  clay,  producing  at  this 
season  an  abundant  growth  of  forage,  chiefly  Medicago  and  Erodium. 

The  same  bituminous  slates  appear  at  San  Buenaventura;  and 
Mount  Hoar,  a  high  mountain  near  the  sea,  a  little  to  the  northwest, 
was  found  to  be  made  up  of  the  same  rock,  as  far  as  examined  along 
its  flanks.  To  the  north  and  northeast  of  the  Mission,  the  hills  are 
deeply  and  extensively  furrowed  by  caiions,  with  very  steep  sides;  the 
slopes  of  one  near  the  sea  were  found  by  actual  measurement  to  be  as 
much  as  60°  to  65°.  Near  the  San  Buenaventura  River  the  strata  have 
a  dip  of  25°  to  30°  ;  but  two  or  three  miles  northeast  of  the  Mission  the 
strike  is  N.  64°  E.,  and  the  dip  from  35°  to  50°.  Everywhere  on  the 
inclined  strata  is  a  deposit  of  more  modern  sand  and  gravel,  nearly 
horizontal,  and  in  some  places  as  much  as  twenty-five  feet  thick. 

Nearly  all  the  boulders  in  the  San  Buenaventura  River  are  of  sand¬ 
stone,  sometimes  metamorphic ;  but  a  few  were  of  granite,  gneiss,  and 
a  dark  hornblendic  or  trappean  rock.  On  the  sea-shore,  boulders  of 
asplialtum  were  seen,  nearly  as  hard  as  anthracite,  and  large  deposits 
are  found  in  place,  on  the  surface,  in  the  vicinity,  as  will  be  more  fully 
noticed  farther  on.  Valuable  beds  of  sulphur  are  reported  to  exist  a 
few  miles  up  the  river. 

The  road  followed  by  our  party,  from  Camp  17,  at  Buenaventura,  to 
Camp  18,  at  Carpinteria,  was  along  the  coast  and  the  base  of  Mount 
Hoar,  which  appeared  to  be  entirely  made  up  of  the  bituminous  slates. 
High  bluffs  or  steep  hills  skirt  the  coast,  showing  everywhere  inclined 


126 


GEOLOGY  OF  THE  COAST  RANGES 


strata,  dipping  from  25°  to  30°  to  the  southwest,  with  a  few  feet  of 
horizontal  beds  of  detrital  material  on  the  top.  The  slates  are  inter- 
stratified  with  fine-grained  sandstones,  and  the  formation  is  undergoing 
rapid  denudation  from  the  action  of  the  resistless  surf  of  the  Pacific. 
The  worn  edges  of  the  strata,  planed  off  and  polished  by  the  waves, 
may  he  seen  for  some  distance  out  from  the  shore  at  low  water.  The 
strike  of  these  rocks  is  here  from  N.  45°  to  55°  W.  No  eruptive  rock 
was  seen  here,  and  only  a  few  granite  boulders  were  observed  on  the 
beach;  hut  immense  numbers  of  sandstone  pebbles  were  seen,  some  of 
which  were  quite  fossiliferous. 

About  five  miles  southeast  of  Carpinteria,  the  rock  presents  exactly 
the  appearance  of  having  had  the  bituminous  matter  burned  out  of  it; 
it  assumes  various  colors,  such  as  bright-red,  rose,  brown,  yellow,  and 
cream-color,  and  it  appears  to  have  been  partially  fused  in  some 
places.  These  colors  are  made  very  conspicuous  by  the  washing  and 
smoothing  of  the  rocks  by  the  Ocean. 

The  slates  are  black  and  highly  bituminous  where  the  outcrop  strikes 
the  sea,  three  miles  to  the  southwest  of  Carpinteria,  and  large  quanti¬ 
ties  of  tarry  asphaltum  flow  from  them.  For  a  mile  or  more  along  the 
shore  the  banks  abound  in  it,  and  it  saturates  the  beach-sand  and  flows 
down  into  the  sea.  Sand,  pebbles,  shells,  and  wood  are  cemented  into 
a  hard  mass  by  it,  the  cement  being  nearly  as  solid  as  the  rock  itself. 
Near  the  “  oil-works”  the  strata  are  almost  vertical,  and  have  a  strike  of 
N.  66°  W.;  but  half  a  mile  farther  south  they  are  much  disturbed  and 
contorted.  They  are  broken,  bent,  and  twisted,  so  as  to  lie  at  every 
possible  angle  of  dip  and  strike,  and  in  the  bent  strata  many  of  the 
curves  are  very  short  and  abrupt.  The  rocks  at  this  point  are  more  or 
less  metamorphosed,  and  the  strata  have  assumed  elegantly  contrasting 
alternations  of  black  and  white,  which  are  rendered  more  conspicuous 
by  the  action  of  the  waves.  In  places  the  rocks  have  been  broken  up 
into  large  masses,  and  these  again  reunited,  still  preserving  their  lines 
of  stratification  with  perfect  distinctness,  as  shown  in  the  annexed 
figure,  which  represents  a  fragment  of  rock,  perfectly  solid,  but  with 
the  stratification  plainly  marked  in  the  different  pieces  of  the  mosaic, 
as  is  shown  in  the  wood-cut  (Fig.  9). 

An  establishment  for  distilling  oil  from  the  asphaltum  was  started 


SOUTH  OF  TIIE  BAY  OF  MONTEREY. 


127 


shortly  before  the  time  our  party  visited  the  place  (March,  1861);  but 
access  to  it  was  not  allowed,  nor  information  given.  It  is  believed, 
however,  to  have  been  a  failure,  both  as  re¬ 
gards  the  quality  of  the  oil  produced  and 
the  profits  of  obtaining  it. 

These  bituminous  slates  extend  along  the 
base  of  the  Santa  Inez  Range  to  the  east, 
and  were  explored  by  our  party  as  far  as  the 
Gaviota  Pass,  about  forty-five  miles  from 
Carpinteria;  they  continue  beyond  this,  but, 
it  is  said,  not  as  far  as  Point  Concepcion. 

The  general  dip  along  this  line  is  to  the 
south ;  but  the  strata  are  exceedingly  contorted,  being  bent  and  twisted 
into  every  possible  variety  of  curve.  They  are  also  metamorphosed 
and  hardened,  and  the  variations  of  hardness  and  color,  as  well  as  the 
elaborate  curvings  of  the  beds,  are  beautifully  displayed  in  the  broad 
level  surface  worn  off  by  the  sea,  and  left  visible  at  low  tide.  These 
contortions  seem  to  be  limited  to  a  rather  narrow  belt  near  the  shore. 
As  we  recede  inland  they  become  less  conspicuous,  and  the  strata  re¬ 
gain  gradually  their  regular  southern  inclination. 

The  chain  of  the  Santa  Inez  rises  to  the  north  of  Santa  Barbara,  a 
conspicuous  object  to  those  approaching  this  place  by  water.  As  far  as 
known,  it  takes  its  origin  at  a  point  due  north  of  Buenaventura,  and 
running  a  little  north  of  west  (hT.  84°  W.)  for  a  distance  of  over  sixty 
miles,  it  meets  the  sea  at  Point  Concepcion.  The  chain  has  its  greatest 
elevation  apparently  near  Santa  Barbara,  where  it  is  about  3800  feet 
high.  To  the  west  of  the  Gaviota  Pass  it  has  an  elevation  of  about 
2500  feet.  The  main  ridge  is  entirely  composed  of  Tertiary  (Miocene) 
sandstones,  without  any  appearance  of  eruptive  rock,  and  also  with 
very  little  metamorphism. 

When  examined  towards  its  eastern  end,  north  of  Carpinteria,  the 
chain  has  the  form  of  a  great  anticlinal  arch,  of  which  the  northern 
portion  has  remained,  while  the  crown  and  the  southern  half  have  been 
removed,  irregularly,  but  with  a  gradual  increase  of  the  denudation  to¬ 
wards  the  sea,  so  as  to  leave  three  distinct  ridges,  as  shown  in  the  an¬ 
nexed  diagram  (Fig.  10),  which  represents  a  section  across  the  hills  at 
this  point. 


Fig.  9. 


BROKEN  AND  RECEMENTED  MASSES  OF 
BITUMINOUS  SLATE. 


128 


GEOLOGY  OF  THE  COAST  RANGES 


This  chain  was  climbed  by  our  party,  at  two  points  between  Carpin- 
teria  and  Santa  Barbara;  namely,  above  the  Hot  Sulphur  Springs,  five 

Fig.  10. 

Section  across  tiie  Santa  Inez  Range,  north  of  Carpinteria. 

S.  N. 


a  be  d 

a.  Bituminous  slate,  b.  Front  ridge  of  sandstone,  dip  S.  30°.  c.  Central  ridge  of  sandstone. 
d.  Main  ridge,  sandstone  with  dip  of  about  30°  to  the  north. 


or  six  miles  east  of  Santa  Barbara,  and  on  the  Tdjon  trail,  three  or  four 
miles  still  farther  east.  At  both  these  points  nearly  the  same  section 
was  obtained.  The  foot-hills  are  of  slate,  the  highest  about  800  feet 
in  altitude,  and  the  strata  much  broken ;  the  main  ridge  is  of  sand¬ 
stone,  3700  to  3800  feet  high,  with  the  dip  always  to  the  north  and  the 
strike  about  east  and  west,  magnetic  (H.  76°  W. — S.  76°  E.) ;  the  sum¬ 
mit  is  rather  broad,  or  made  up  of  several  (usually  three)  distinct  ele¬ 
vations,  more  or  less  connected  by  transverse  ridges ;  these  sandstones 
are  overlaid  on  the  north  by  slates  and  fine  grits,  sometimes  a  little 
metamorphosed. 

The  Hot  Springs  are  in  a  precipitous  canon  on  the  side  of  the  range, 
at  an  elevation  of  1426  feet  above  the  sea,  near  the  base  of  steep  preci¬ 
pices  of  unaltered  sandstone.  The  waters  are  highly  charged  with 
sulphur,  and  the  springs  had  the  temperature  (March  18, 1861)  of  112°, 
115°,  115°,  114°.  5  and  118°,  the  larger  ones  being  usually  the  warmer; 
but  the  most  copious  one,  at  the  bath,  was  115°.  In  ascending  the 
ridge  back  of  this,  the  slopes  are  very  steep  along  the  broken  edges  of 
the  strata,  until  the  crest  is  attained,  which  is  of  sandstone,  covered 
with  weathered  boulders  of  the  same  material.  The  rock  is  red,  rather 
coarse-grained,  and  appeared  quite  destitute  of  fossils.  About  two 
miles  back,  along  a  transverse  ridge,  and  over  a  small  elevation  or 
knob,  the  northern  and  highest  ridge  was  reached,  and  was  found  to 
be  made  up  of  fine  sandstones  and  slates,  generally  somewhat  meta¬ 
morphosed.  The  dip  is  always  to  the  north,  and  at  an  angle  of  from 
50°  to  70°,  while  in  places  the  rocks  stand  nearly  vertical.  The  highest 


SOUTH  OF  THE  BAY  OF  MONTEREY. 


129 


point  measured  was  3638  feet  above  the 
sea;  but  higher  points  were  seen  both  east 
and  west,  the  most  elevated  of  which  was 
estimated  at  3800  feet  above  the  sea. 

On  an  excursion  made  to  the  “  Coal 
Mines,”  by  way  of  the  “  T£jon  trail,”  a 
disused  and  almost  impassable  bridle-path, 
the  north  slope  of  this  range  was  passed 
over  a  little  east  of  the  point  just  noticed, 
and  about  six  miles  east  of  Santa  Barbara. 
Metamorpliic  rock  and  conglomerate  were 
seen  on  that  side,  as  also  serpentine  at  the 
north  base  of  the  ridge.  An  idea  of  the 
structure  of  the  chain  at  this  point  may  be 
obtained  from  the  annexed  section.  (Fig. 
ii.) 

The  horizontal  distances  are  approximate 
only.  At  the  point  where  this  section  was 
taken,  and  as  far  east  as  the  chain  can  be 
seen  from  the  summit,  all  the  strata  of 
the  main  chain  have  a  dip  to  the  north; 
but,  about  two  or  three  miles  west,  the  dip 
changes,  and  the  lar^e  masses  of  sandstone 
have  a  southern  dip. 

The  chain  was  again  examined  in  the 
canon  back  of  the  Mission  of  Santa  Bar¬ 
bara,  where  the  strata  all  have  a  southern 
dip,  as  mentioned  above,  the  broken  edges 
of  the  uplifted  beds  forming  a  very  ragged 
outline  against  the  sky.  At  the  base,  the 
dip  is  very  high,  sometimes  almost  vertical, 
but  not  a  trace  of  either  eruptive  or  metaT 
morphic  rock  was  seen  on  this  section. 

Figure  12  will  serve  to  give  an  idea  of 
the  position  of  the  rock  in  this  section  of 
the  Santa  Inez,  and  will  also  exhibit  the 


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GEOL.  VOL.  T. — 17 


Sea*  f>;  Lerel  region  underlaid  by  bituminous  slates,  dipping  south,  c,  d.  Bituminous  slates  with  variable  dip.  e.  Sandstone  dipping  north.  /.  Hot 
Sulphur  Springs,  g.  Unaltered  sandstone.  //.  Crest  of  the  range  of  slates  and  sandstones,  slightly  metamorphic.  i.  Unaltered  sandstones.  Metamorphic 
slates,  m.  Serpentine,  n.  Metamorphic  slates. 


130 


GEOLOGY  OF  THE  COAST  RANGES 


relations  of  the  newer  strata  near  the  shore,  of  which  more  will  be  said 
farther  on.  Near  the  shore,  the  bituminous  shales  and  slates  may  he 
seen,  in  a  highly  contorted  position,  and  somewhat  metamorphosed. 

Gradually  they  acquire  their  regular 
southern  dip,  and  lose  their  meta- 
morpliic  character.  The  Old  Mis¬ 
sion  is  built  on  these  slates,  and  the 
slopes  behind  it  are  covered  with 


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which  have  been  washed  down  from 
the  heights  above. 

Farther  up  the  mountain,  as  seen 
in  this  section,  we  come  to  the  sand¬ 
stone,  first  red  and  then  gray,  with 
very  high  northerly  dip,  quite  heavy- 
bedded,  and  presenting  a  very  grand 
appearance  with  its  lofty  battlement- 
ed  edges  turned  up  to  the  sky.  This 
sandstone  continues  to  the  summit  of 
the  ridge,  which  was  not  crossed  at 
this  point.  The  very  highest  points 
of  the  Sierra  Santa  Inez  cannot  be 
much  less  than  4000  feet,  as  esti¬ 
mated  from  the  point  measured,  and 
found  to  be  3638  feet  high,  and  as 
the  diameter  of  the  chain  from  north 
to  south  is  only  about  six  miles,  an 
idea  may  be  formed  of  its  precipitous 
character,  the  southern  slope  being 
often  as  high  as  30°,  and  in  some 
places  as  much  as  37°. 

The  reversal  of  dip  in  the  chain 
occurs  about  four  miles  northeast  of  Santa  Barbara,  where  it  appears 
that  the  axis  crosses  the  ridge  diagonally  from  northwest  to  southeast; 
but  it  was  not  possible  to  examine  this  line  satisfactorily.  It  was  cer¬ 
tain,  however,  that  this  extraordinary  change  of  dip  was  not  connected 


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SOUTH  OF  THE  BAY  OF  MONTEREY. 


131 


with  any  appearance  of  intrusive  or  disturbing  rock  on  the  surface. 
This  change  of  the  dip  of  the  whole  mass  of  the  strata  of  the  mountain 
is  the  more  remarkable,  as  being  not  evidenced  by  any  break  in  the 
ridge  itself.  On  this  question  some  remarks  will  be  made  farther  on 
in  this  Report. 

Wherever  the  chain  was  examined  to  the  west  of  the  section  last 
given,  as  far  as  a  point  a  few  miles  to  the  west  of  Gaviota  Pass,  the 
rock  had  always  a  dip  to  the  south,  at  a  high  angle,  the  crest  consist¬ 
ing  of  the  broken  edges  of  the  sandstone,  the  bituminous  slate  resting 
on  its  flanks  •  in  the  foot-hills,  and  both  formations  appearing  entirely 


conformable  with  each  other. 

The  bituminous  slate  is  admirably  exposed  all  along  the  sea-shore 
for  several  miles  to  the  west  of  Santa  Barbarav  At  a  point  one  mile  in 
that  direction,  where  the  shales  were  planed  down  to  the  level  of  the 
ocean,  and  the  stratification  could  be  most  beautifully  seen,  the  strike 
was  noticed  to  be  N.  79°  E.,  and  the  dip  60°  to  the  south.  In  some 
places  the  slate  forms  low  cliffs  by  the  edge  of  the  ocean :  in  others  it 
has  been  denuded,  and  it  is  now  covered  by  a  more  recent  deposit. 
The  complication  of  the  disturbances  in  these  strata  may  be  well  seen 
in  the  annexed  cut,  which  represents  a  length  of  seventy-five  feet  along 


Fig.  13. 


FOLDINGS  OF  BITUMINOUS  SLATE  NEAR ‘SANTA  BARBARA. 


the  base  of  the  bluff*,  and  in  which  the  foldings  of  the  strata  are  accu¬ 
rately  copied,  in  their  principal  curves,  so  far  as  is  possible  on  so 
small  a  scale.  These  disturbances  seem  particularly  common  in  the 
immediate  vicinity  of  Santa  Barbara.  In  some  localities  the  rock  has 
evidently  been  on  fire,  and  the  bituminous  matter  having  been  burned 
out — the  operation  continuing  for  several  years,  as  it  is  said — the  slates 
are  left  of  various  shades  of  red,  produced  by  the  oxidation  ot  the  iron. 


132 


GEOLOGY  OF  THE  COAST  RANGES 


The  asphaltum,  or  hardened  bituminous  matter,  occurs  in  the  great¬ 
est  abundance  on  the  shore  at  Hill’s  Ranch,  about  six  miles  west  of 
Santa  Barbara,  and  lies  along  the  beach  for  a  distance  of  a  mile,  in 
large  masses.  The  bituminous  slate  is  here  covered  unconformably,  as 
at  Santa  Barbara,  by  a  heavy  deposit  of  Post-Pliocene  age,  which  here 
attains  a  thickness  of  from  eighty  to  one  hundred  feet. 

Fig.  14. 


Post-Pliocene. 

Asphaltum. 

High-water  mark. 

Ocean. 

Bituminous  slates. 

CROSS-SECTION  OF  ASPHALTUM  LOCALITY  AT  HILL’S  RANCH. 

The  two  sections  (Figs.  14  and  15)  exhibit  the  relations  of  the  forma- 

9 

tions  here,  and  the  position  of  the  asphaltum.  The  bituminous  slates, 
which  are  highly  contorted  and  turned  up  on  edge,  lie  nearly  on  a  level 
with  the  ocean.  On  their  edges  rests  a  body  of  soft  arenaceous,  and 
loose  gravelly,  materials,  sometimes  very  slightly  consolidated,  in  which 
are  long  fissures  filled  with  asphaltum ;  this  in  some  cases  has  risen  to 
the  surface  of  the  formation  and  become  accumulated,  in  large  masses, 
in  the  overlying  recent  or  alluvial  formation.  The  gradual  erosion  of 
the  cliff  has  exposed  large  masses  of  the  asphaltum,  which  have  fallen 

Fig.  15. 

Recent. 


Post-Pliocene. 

Sea-beach  with  asphaltum. 

Ocean. 

FRONT  VIEW  OF  ASPHALTUM  LOCALITY  AT  HILL’S  RANCH. 

down  and  accumulated  in  considerable  quantity  on  the  beach,  as  repre¬ 
sented  in  the  longitudinal  section.  This  locality  has,  for  a  long  time, 
furnished  all  the  asphaltum  used  for  roofs  and  pavements  in  San  Fran¬ 
cisco,  as  it  lies  most  convenient  to  the  sea.  In  1861  this  material  was 


SOUTH  OF  THE  BAY  OF  MONTEREY. 


1 


Q  O 

oo 


sold  in  the  city  for  $15  per  ton,  the  chief  expense  of  obtaining  it  being 
that  arising  from  the  difficulty  of  getting  it  on  board  the  vessel,  on  a 
coast  exposed  to  the  Pacific  swell.  It  will  be  noticed  that  the  asphal- 
tum  lies  in  the  arenaceous  rock  or  sandstone,  over  the  bituminous 
shales,  from  which  it  was  derived,  and  from  which  it  has  been  forced 
out  probably  b}’  heat  and  pressure.  Through  the  slates  themselves,  the 
bituminous  material  appears  to  be  uniformly  diffused,  and  not  con¬ 
centrated  into  pure  masses.  The  asphaltum,  as  it  lies  on  the  shore,  is 
necessarily  much  mixed  with  sand:  specimens  selected  as  of  fair  quality 
contained  about  sixty  per  cent,  of  that  material.  No  appearances  of 
any  soft,  liquid,  or  tarry  matter  were  noticed  at  this  locality. 

Extending  west  from  Hill’s  Ranch,  the  bituminous  slate  occupies  a 
strip  from  one  to  three  miles  wide,  between  the  rugged  Santa  Inez 
Range  and  the  sea.  It  forms  rounded  hills,  very  green  and  grassy, 
the  soil  being  fertile  and  retentive  of  moisture.  The  junction  of  the 
slates  and  sandstones  could  be  accurately  traced  on  the  surface  by  the 
character  of  the  soil  and  vegetation,  as  well  as  by  the  form  of  the  hills. 
In  ascending  from  the  sea  towards  the  interior,  tlie  chaparral,  indicating 
a  dry  soil,  is  first  met  with  on  striking  the  sandstone.  The  ocean  fogs 
help  to  supply  this  region  with  moisture,  and  few  ranches  in  California 
can  equal  in  beauty  and  fertility  those  situated  on  the  bituminous  slates 
along  this  part  of  the  coast.  Of  these,  the  ranches  of  Mr.  Hill  and  Dr. 
Denn  (Dos  Pueblos)  and  the  Rancho  El  Capitan  are  the  most  noted. 
At  the  Tortegas  Ranch  the  belt  of  slate  is  narrower,  appearing  to  be 
about  one  and  a  half  miles  wide,  which  width  it  holds  as  far  as  we 
traced  it,  to  beyond  the  Gaviota  Pass.  Throughout  the  whole  of  this 
extent  it  has  a  strike  nearly  parallel  with  that  of  the  chain,  and  every¬ 
where  a  southern  dip,  conformable  to  that  of  the  sandstone  which  un¬ 
derlies  it.  At  one  locality,  a  short  distance  west  of  Camp  20,  in  the 
cliffs  at  the  base  of  the  ranch  called  El  Capitan,  the  sea  has  made  a 
section  very  nearly  at  right-angles  to  the  strike,  and  the  dip  is  seen 
to  be  quite  uniform,  being  everywhere  from  30°  to  40°.  A  portion 
without  apparent  break  or  fault  was  measured  along  the  bluff  on  the 
beach,  which  represented  a  perpendicular  thickness  of  about  1300  feet 
of  slate.  The  actual  thickness  is,  however,  much  greater,  probably 
more  than  twice  as  great;  but,  owing  to  breaks  and  faults,  this  is  the 


134 


GEOLOGY  OF  THE  COAST  RANGES 


greatest  thickness  measured  in  any  one  place,  where  the  rocks  were 
% 

unquestionably  not  folded,  and  where  the  whole  could  be  minutely  ex¬ 
amined.  This  portion  of  the  slate  seemed  less  bituminous  than  that 
at  Santa  Barbara,  but  still  it  was,  in  places,  highly  charged  with  this 
substance. 

On  referring  to  the  section  on  page  130,  it  will  be  seen  that  the  strip 
of  land  between  the  Ocean  and  the  Mission  of  Santa  Barbara  is  occu¬ 
pied  by  low  hills;  these  rise  to  the  height  of  433  feet  in  the  highest 
place,  and  they  are  made  up  of  strata  which  are  nearly  horizontal,  or 

have  only  a  slight  seaward  dip,  and  which  rest  on  the  upturned  edges 

0 

of  the  bituminous  slates.  This  formation  is  well  exposed  in  the  cliffs 
along  the  shore  west  of  Santa  Barbara,  and  in  some  places  attains  a 
thickness  of  a  hundred  feet.  It  consists  of  strata  of  coarse  gravel  and 
sand,  some  of  which  are  consolidated  into  the  hardest  sandstones,  while 
others  are  still  quite  soft  and  easily  disintegrated.  These  strata,  them¬ 
selves  unconformable  with  the  slates  below,  are  again  overlaid  uncon- 
formably  by  the  recent  or  modern  alluvial  deposits,  as  will  be  seen  on 
the  section  at  Hill’s  Ranch,  page  132.  Along  the  sea-shore  the  beds  in 
question  have  been  very  irregularly  worn  and  denuded  by  the  action  of 
the  sea,  as  may  be  noticed  on  the  section  in  the  wood-cut  annexed 

(Fig.  16),  taken  about  a  mile  west 
of  Santa  Barbara,  and  showing 
the  junction  of  the  recent  beach 
deposits  with  the  denuded  and  ir¬ 
regularly-worn  mass  of  the  older 
formations. 

This  formation  thus  exposed  on 
the  beach  at  Santa  Barbara  is  ex¬ 
tremely  rich  in  fossils,  nearly  all 
of  which  are  of  living,  while  a 
small  number  are  of  extinct  species.  The  mollusca  collected  here  have 
been  referred  to  P.  B.  Carpenter,  for  comparison  with  the  now  living 
Pacific  coast  species,  and  the  results  of  his  investigation  will  be  given 
in  the  second  volume  of  the  Palaeontology,  forming  a  part  of  the  pub¬ 
lications  of  the  Survey.  The  fossils  of  the  locality  near  the  town,  from 
the  locality  at  b ,  Fig.  12,  and  which  are  referred  to  the  Pliocene  epoch 
by  Mr.  Gabb,  will  also  be  noticed  and  described  in  the  same  volume. 


IlCVrKi  tit 


BEACH  SECTION,  NEAR  SANTA  BARBARA. 

a.  Soft  beach  sand.  b.  Rolled  beach  pebbles. 
c  Fine  detritus  and  sand,  with  soil  on  top.  d. 
Hard  sandstone. 


SOUTH  OF  THE  BAY  OF  MONTEREY. 


135 


In  crossing  the  Gaviota  Pass,  a  tooth  and  some  hones  of  a  mastodon 
were  found,  oil  Dr.  Derm’s  ranch,  in  the  superficial  detritus,  at  the 
bottom  of  a  layer  of  clay  about  four  feet  thick,  and  resting  on  a  stra¬ 
tum  of  fine  sand.  These  remains  were  in  too  friable  a  condition  to 
admit  of  their  being  removed.  The  summit  of  the  pass  is  about  1000 
feet  above  the  sea,  and  the  elevation  of  the  mountains  to  the  west  of  it 
nearly  2500  feet.  Descending  the  chain  on  the  north  side,  by  the  Ga¬ 
viota  Pass,  we  come  to  the  Valley  of  Santa  Inez,  which  is  several  miles 
wide  at  the  Mission  de  la  Purisima ;  but  narrower  above  and  below  it. 
There  is  but  little  level  ground  in  the  valley;  but  it  consists  rather  of 
low  rounded  hills  of  fossiliferous  strata,  of  Miocene  Tertiary  age.  A 
section  across  the  Santa  Inez  chain,  taken  one  mile  east  of  the  Gaviota 
Pass,  is  given  in  the  annexed  wood-cut  (Fig.  17). 


Fig.  17. 


Section  of  Sierra  Santa  Inez,  east  of  Gaviota  Pass. 

Length,  6  miles ;  scale  of  heights  and  distances,  equal. 


a  h  c  d 

a .  Bituminous  slates,  h  to  c.  Unaltered  sandstones  of  Miocene  age,  with  southerly  dip.  d.  Low 

hills  of  Santa  Inez  Plain. 


The  following  species,  referred  by  Mr.  Gabb  to  the  Miocene,  were 
found  in  the  Santa  Inez  mountains  and  valley,  and  in  the  hills  north 
of  Camp  29,  at  the  Najolmi  Ranch : 


Neverita  Recluziana,  Saxidomus  aratus, 

Turritella  Inezana,  Crassatella  collina, 

T.  YARIATA,  PECTEN  PABLOENSIS. 

Purpura  petrosa, 

% 

The  three  chains,  Santa  Inez,  San  Rafael,  and  Cuyamas  are  nearlj 
parallel,  and  succeed  each  other  from  south  to  north  in  the  outer 
named.  The  Santa  Inez  is  the  highest  and  best  defined,  and  has 
already  been  described  in  sufficient  detail.  The  San  Rafael  occupies 
the  region  between  the  Santa  Inez  and  Santa  Maria  Rivers,  and  the 
Cuyamas  chain  has  the  river  of  the  same  name  on  the  1101th.  IIicm 


130 


GEOLOGY  OF  THE  COAST  RANGES 


ridges  were  traversed  by  our  party  at  a  point  about  15  miles  above  the 
Santa  Inez  Mission,  and  in  a  direction  nearly  transverse  to  their  trend. 
The  San  Rafael  chain,  where  crossed,  north  of  the  Santa  Inez  River, 
was  from  3800  to  4000  feet  high.  The  rocks  seen  were  sandstones 
alternating  with  slates,  the  latter  often  dark-colored.  Mountains  five 
or  six  miles  east  and  northeast  had  much  snow  on  them  (March,  1861), 
and  were  probably  fully  5000  feet  high.  On  the  north  side  of  this 
range,  the  rocks  were  examined  more  particularly  in  the  neighborhood 
of  a  supposed  coal-bed,  where  some  explorations  had  been  made  in 
search  of  that  substance.  The  strata  here  were  slates  and  sandstones, 
interst ratified,  having  a  strike  of  about  east  and  west,  magnetic,  or  N. 
76°  W.,  S.  76°  E.,  and  standing  nearly  vertical.  The  carbonaceous 
matter  formed  thin  lenticular  masses,  which  were  seldom  over  an  inch 
thick,  where  examined  by  us ;  but  some  were  said  to  have  been  found 
as  much  as  five  or  six  inches  thick  in  places. 

No  eruptive,  and  but  few  metamorphic,  rocks  were  seen  on  this  line 
of  section.  Serpentine  was  noticed,  however,  near  the  Santa  Inez 
River,  as  shown  in  the  section  given  on  page  129;  this  mass  was  about 
200  feet  in  thickness,  and  extended  over  a  mile  in  length. 

As  seen  from  the  higher  ridges,  between  the  Santa  Inez  and  Santa 
Maria  Rivers,  the  surrounding  country  appears  to  present  two  princi¬ 
pal  higher  ridges,  running  nearly  east  and  west ;  of  these,  the  southern 
is  the  Santa  Inez,  and  the  northern  was  supposed  to  be  the  Santa  Lucia 
or  Cuyamas  Range,  although  no  generally  recognized  name  could  be 
obtained  for  it;  the  space  between  these  ranges,  which  is  twelve  or 
fifteen  miles  wide,  is  entirely  occupied  by  lower  ridges,  not  continuous, 
but  much  broken,  the  higher  ones  parallel  with  the  Santa  Inez,  the 
others  transverse,  or  having  a  general  northwest  and  southeast  direc¬ 
tion.  The  strike  of  the  sandstones  in  these  intermediate  ridges  seemed 
as  variable  as  the  direction  of  the  ridges  themselves. 

The  region  to  the  west  of  the  San  Rafael  Range,  between  the  Santa 
Inez  and  Cuyamas  Rivers,  was  cursorily  examined  by  our  party,  which 
camped  once  (Camp  22)  at  Alamo  Pintado,  four  miles  north  of  the 
Mission  of  Santa  Inez,  and  again  (Camp  23)  at  Foxin’s  Ranch,  about 
twenty-five  miles  due  east  of  Point  Purisima.  The  region  is  occupied 
by  hills  of  moderate  height.  No  metamorphic  rock  was  seen;  but 


SOUTH  OF  THE  BAY  OF  MONTEREY. 


137 


pebbles  of  serpentine  and  metamorphic  sandstone  were  noticed,  espe¬ 
cially  for  three  or  four  miles  north  of  Alamo  Pintado.  The  road  tra¬ 
velled  over  by  .the  party  led  up  a  valley  in  a  northerly  direction  to 
about  eight  miles  from  the  Santa  Inez  Mission ;  thence  it  crossed  low 
hills,  following  a  northwesterly  course  for  eight  or  nine  miles.  These 
hills  were  covered  with  gravel  derived  from  the  bituminous  slates.  At 
times,  especially  near  the  Santa  Maria  River,  the  hills  were  capped  by 
a  modern  horizontal  deposit  (Post-Pliocene  ?).  The  underlying  rock, 
when  seen,  was  the  bituminous  slate,  sometimes  dipping  to  the  north, 
and  sometimes  to  the  south.  The  valley  in  which  Foxin’s  Ranch 
(Camp  23)  is  situated  has  a  course  at  that  place  of  N.  56°  W.  Follow¬ 
ing  this  valley  down  towards  the  ranch,  the  elevations  on  the  north 
were  found  to  be  of  bituminous  slate,  dipping  north ;  on  the  other  side, 
the  hills  were  lower,  and  generally  capped  by  horizontal  strata  of  semi- 
consolidated  materials,  forming  tables. 

Near  Foxin’s,  on  the  south  side  of  the  valley,  there  were  hills  of 
nearly  horizontal  strata  from  200  to  300  feet  high,  the  north  slopes  of 
which  were  very  steep,  usually  about  35°,  but  sometimes  as  much  as 
37°,  yet  perfectly  grassed.  Beneath  the  soft  sandstone  which  made  up 
the  principal  part  of  these  hills  was  a  stratum  of  infusorial  rock,  resem¬ 
bling  chalk  in  appearance,  exceedingly  light,  its  specific  gravity  not 
being  more  than  .6  or  .7 ;  the  thickness  of  this  stratum  was  over  twenty 
feet.  The  age  of  this  formation  is  not  yet  definitely  ascertained. 

North  of  the  valley,  at  Foxin’s,  the  bituminous  slate  occurs,  with  a 
high  dip  to  the  north,  and  asphaltum  is  found  in  several  localities  near. 
In  places  the  slates  are  altered  and  silicified,  sometimes  resembling 
semi-opal  in  appearance,  the  finest  laminae  of  the  original  structure 
being  preserved.  On  this  ranch,  in  the  bed  of  a  spring,  which  disap¬ 
peared  a  few  years  since  after  an  earthquake,  the  bones  of  a  whale  had 
been  found,  but  only  a  few  fragments  could  be  secured  by  our  party; 
these  bones  were  obtained  about  three  feet  beneath  the  surface. 

There  seems  to  be  considerable  uncertainty  in  regard  to  the  names 
“  Cuyamas”  and  “  Santa  Maria,”  as  applied  to  the  river  running  north 
of  the  San  Rafael  chain,  and  its  branches ;  the  lower  part  of  the  river 
seems  to  be  known  by  those  living  in  that  vicinity  as  the  Santa  Maria, 
and  the  northern  and  larger  branch  as  the  Cuyamas,  the  smaller  branch 


OEOL.  VOL.  I. — IS 


138 


GEOLOGY  OF  THE  COAST  RANGES 


in  this  case  giving  its  name  to  the  main  river.  There  is  quite  an 
extensive  plain  at  the  mouth  of  the  Santa  Maria,  called  “  Guadelupe 
Largo,”  on  which  are  situated  the  Ripoma  and  Guadelupe  Ranches. 
On  the  south  side  of  this  plain  there  are  several  well-marked  terraces. 
On  the  north,  near  the  Ripoma  Ranch  (Camp  24),  there  are  high,  sharp 
hills,  of  strata  more  or  less  metam orphic  and  having  a  high  northern 
dip.  A  series  of  tables  or  terraces  lies  between  the  main  ridges  and 
the  plain,  through  which  run  lines  of  highly  metamorphie  rock,  some¬ 
times  silicified,  so  as  to  be  converted  into  almost  pure  quartz,  while 
other  portions  are  more  argillaceous,  but  the  whole  very  hard  and  ring¬ 
ing  like  iron  under  the  hammer.  The  stratification,  however,  is  not  at 
all  obliterated  in  these  metamorphie  rocks,  except  in  the  case  of  the  ser¬ 
pentine  ;  but  it  is  much  more  evident  in  the  large  masses  than  it  would 
be  in  hand-specimens.  Rear  the  base  of  the  ridge  was  some  very  hard 
and  trappean-looking  rock;  but  it  appeared,  on  examination,  to  be 
only  altered  sandstone.  The  altered  slates  had  the  appearance  of  hav¬ 
ing  been  silicified  by  hot  water,  which  had  left  them  in  the  condition 
of  a  semi-opaline  mass,  but  with  the  fine  lines  of  stratification  distinctly 
preserved.  The  annexed  wood-cut  (Fig.  18)  is  intended  to  represent  an 
approximate  section  of  the  hills  at  Ripoma,  and  especially  to  convey  an 


Fig.  18. 

Section  near  Ripoma  Ranch. 


a.  Cuyamas  Plain,  b.  Table,  at  base  of  hills,  with  lines  of  metamorphie  rock.  c.  Highly  altered 

sandstone,  d.  Metamorphie  beds.  e.  Unaltered  slates. 


idea  of  the  way  in  which  these  lines  of  strata  have  become  metamor¬ 
phosed  in  parallel  bands,  showing  clearly  that  these  altered  rocks  are 
not  intrusive  masses,  disturbing  or  elevating  the  chain.  In  some  of 
the  foot-hills,  the  metamorphie  and  harder  strata  alternated  with  the 
softer  ones,  giving  a  beautiful  terraced  appearance  to  the  surface.  This 
ridge  has  about  the  same  direction  as  the  strike  of  the  strata,  namely, 


SOUTH  OF  THE  BAY  OF  MONTEREY. 


139 


N.  56°  W.,  their  direction  being  quite  regular;  the  elevation  of  these 
hills  is  from  1800  to  2000  feet  above  the  valley. 

Between  Nipoma  and  the  Arroyo  Grande,  these  metamorphic  hills 
continue,  some  of  them  very  sharp  in  outline  and  rising  to  the  height 
of  1000  feet.  The  ridges  are  much  cut  up  by  canons  with  precipitous 
sides,  and  have  a  peculiar  appearance,  from  the  alternations  of  the  hard 
metamorphic  strata  with  the  softer  unaltered  ones. 

Near  Camp  25,  on  the  Arroyo  Grande,  about  three  miles  below 
Branch’s  house,  on  the  Santa  Manuela  Ranch,  the  bituminous  slate 
was  observed,  having  a  dip  to  the  north  of  from  40°  to  80°,  and  a 
strike  of  N.  56°  W.  to  N.  76°  W.  Large  deposits  of  asphaltum  occur 
on  this  ranch,  which  is  one  of  those  recently  acquired  by  oil-specula¬ 
tors,  and  on  which  it  is  claimed  that  oil-wells  may  be  bored  with  every 
probability  of  success. 

The  Valley  of  San  Luis  Obispo  extends  in  a  nearly  northwest  and 
southeast  direction  from  Estero  Bay,  on  the  Pacific,  nearly  to  the 
Arroyo  Grande,  a  distance  of  about  twenty  miles  ;  it  has  a  width  ot 
from  three  to  five  miles.  It  embraces  the  San  Luis  Valley,  so  called, 
and  the  Canada  de  los  Osos,  as  well  as  the  Canada  de  las  Piedras.  Be¬ 
tween  this  valley  and  the  sea  there  is  a  range  of  hills,  rising  to  the 
height  of  over  2200  feet  at  its  northwest  end,  but  decreasing  in  eleva¬ 
tion  towards  the  southeast,  and  finally  connecting  with  the  Santa  Lucia 
Range,  a  little  to  the  south  of  the  Arroyo  Grande.  The  Santa  Lucia 
Mountains  extend  along  the  northeast  side  of  the  Valley  of  San  Luis 
Obispo,  having  a  range  of  sharp,  conical  hills,  called  “  The  Buttes,” 
at  their  base.  The  valley  opens  out  to  the  sea,  forming  a  wind-gap, 
like  the  Salinas  Valley;  but  it  is  chiefly  drained  by  the  San  Luis  Creek, 
which  cuts  through  the  chain  of  hills  on  the  southwest,  emptying 
into  the  Ocean  at  the  Bay  of  San  Luis.  Near  the  centre  of  the  valley 
is  a  swamp  or  lagoon,  which  in  very  wet  weather  is  drained  to  the 
northwest. 

The  San  Luis  Valley  is  covered  with  a  superficial  deposit  of  detritus, 
in  places  twenty  or  thirty  feet  thick,  in  others  less.  The  underlying 
rock  is  sandstone,  occasionally  metamorphic,  especially  near  the  edge 
of  the  valley,  the  elevation  of  which,  at  Camp  26,  two  miles  southeast 
of  San  Luis  village,  was  found  to  be  198  feet  above  the  sea. 


140 


GEOLOGY  OF  THE  COAST  RANGES 


There  being:  no  designation  in  current  use  for  the  chain  of  moun- 
tains  on  the  west  and  southwest  of  the  San  Luis  Valley,  it  may  for 
convenience  and  with  propriety  he  called  the  San  Luis  Lange.  It  was 
examined  by  our  party  along  two  lines  of  section,  one  where  the  San 
Luis  Creek  cuts  through  it,  and  the  other  eight  or  nine  miles  to  the 
northwest  of  this,  at  Wilson’s  Ranch,  where  is  a  well-known  locality  of 
the  gigantic  fossil  oysters  ( Ostrea  Titan).  At  and  near  the  San  Luis 
Creek,  and  on  the  road  to  the  bay,  the  highest  points  in  the  range  are 
about  2000  feet  above  the  sea,  and  the  chain  is  deeply  cut  into  ridges, 
by  erosion  chiefly,  although  the  strata  are  much  broken  by  upheaval. 
Much  light-colored  slate  exists  in  the  mass.of  the  chain,  and  it  was  sup¬ 
posed  to  belong  to  the  bitqminous  slate  series.  The  strike  of  these  rocks 
is  variable,  but,  in  the  main,  nearly  that  of  the  chain  itself.  The  dip 
is  still  more  variable,  being  generally  to  the  south  on  the  northern  side, 
nearly  vertical  in  the  centre,  and  to  the  north  on  the  southern  edge,  the 
range  having  a  decided  synclinal  structure,  as  may  be  seen  from  the 
section  given  on  page  144.  Near  the  northern  edge  of  this  range  sev¬ 
eral  masses  of  serpentine  were  seen,  and  some  metamorphic  rock,  as 
also  a  belt  of  very  compact  limestone,  containing  fossil  oysters.  No 
metamorphic  rock  was  seen  on  the  Pacific  side  of  these  mountains. 
At  the  bay,  the  rock  was  light-colored  and  highly  argillaceous,  having 
a  strike  of  N.  21°  W.,  and  a  dip  of  33°  to  the  north. 

Where  visited,  near  Mr.  Wilson’s,  at  the  locality  of  the  large  oysters, 
the  structure  of  the  chain  was  much  less  regular,  there  being  frequent 
developments  of  highly  metamorphic  rock,  and  possibly  some  eruptive 
masses.  Professor  Brewer,  however,  is  decidedly  of  the  opinion  that 
these  eruptive-looking  rocks  are,  in  reality,  indicative  of  fissures  along 
which  metamorphic  action  has  taken  place,  as  has  been  noticed  in  so 
many  other  localities  in  the  Coast  Ranges.  These  lines  of  altered  or 
eruptive  rock  do  not  run  parallel  with  the  strike  of  the  strata,  but  cross 
them  in  an  east  and  west  direction.  They  are  certainly  not  the  cause 
of  the  upheaval  of  this  chain,  and  do  not  form  what  could  by  any  pos¬ 
sibility  be  called  an  “  axial  rock.” 

The  principal  locality  of  fossil  oysters  is  near  the  summit  of  a  ridge, 
about  2000  feet  high,  and  three  miles  S.  40°  W.  from  Mr.  Wilson’s 
house.  There  are  three  outcrops  of  fossiliferous  strata,  running  in  a 


SOUTH  OF  THE  BAY  OF  MONTEREY. 


141 


nearly  east  and  west  direction,  and  which  have  been  traced  for  a  dis¬ 
tance  of  about  a  mile.  The  western  outcrop  is  at  the  summit  of  the 
hill,  where  the  shells  are  contained  in  a  very  compact  limestone;  the 
other  fossiliferous  beds  are  in  a  more  or  less  calcareous  sandstone,  hav¬ 
ing  a  high  dip  to  the  south.  The  oysters  are  very  numerous,  adher¬ 
ing  together  in  large  masses,  as  in  their  natural  beds,  and  weathered 
specimens  were  formerly  so  abundant  that  they  were  gathered  up  and 
burned  for  lime.  It  is  said  that  single  ones  have  been  found,  weighing 
thirty  pounds;  the  largest  collected  by  us  weighed  about  sixteen.  The 
annexed  section  (Fig.  19)  shows  the  position  of  the  rocks  in  this  vicinity. 

Fig.  19. 

Section  across  the  Canada  de  los  Osos. 

L<  n*:th,  seven  miles  ;  direction.  N.  E.— S.  W. 


a.  Metamorphic  rock,  e,  e,  e.  Serpentine,  c.  Stream  and  swamp  in  the  Canada  de  los  Osos. 
in,  »i.  Hill  of  sandstone,  somewhat  metamorphic  on  the  south  side,  with  a  band  of  serpentine  pass¬ 
ing  through  it  at  e.  h .  Metamorphic.  g .  Oyster-shell  beds. 

In  this  section  the  elevations  are  only  approximate;  the  Butte,  or  hill 
in  the  valley,  m,  m,  is  about  1800  feet  high.  Owing  to  the  broken  cha¬ 
racter  of  the  strata,  however,  no  section  can  be  made  which  shall  be 
anything  more  than  an  approximate  and  somewhat  ideal  one. 

Skirting  the  Sierra  Santa  Lucia  on  the  southwest  side,  and  extend¬ 
ing  into  the  San  Luis  Plain,  in  a  southeast  direction,  is  a  chain  of 
sharp,  more  or  less  isolated  hills,  called  atlie  Buttes.”  These  termi¬ 
nate  on  the  northwest  in  the  Moro  Rock,  a  precipitous  mass  of  rock  in 
the  Estero  Bay;  and,  on  the  southeast,  gradually  sink  in  low,  scattered 
hills  on  the  San  Luis  Plain.  The  higher  ones  rise  to  from  1500  to  1800 
feet.  As  seen  from  the  summit  of  the  Santa  Lucia,  northeast  of  San 
Luis,  they  appear  to  lie  in  a  nearly  straight  line,  and  from  that  point 
twenty-one  peaks  can  be  seen  in  this  range,  of  which  eight  or  nine  are 
predominant.  So  far  as  examined,  these  Buttes  are  made  up  of  light- 
gray  trachyte  or  trachytic  porphyry.  A  belt  of  serpentine  lies  along 


142 


GEOLOGY  OF  THE  COAST  RANGES 


their  southern  base,  becoming  wider  as  we  go  towards  the  southeast, 
and  the  Buttes  south  of  the  town  of  San  Luis  are  almost  exclusively  of 
this  rock.  The  serpentine  Buttes  are  more  rounded  in  outline  than  the 
trachytic,  and  these  latter  are  very  rocky  and  steep,  with  many  rounded 
boulders  on  the  surface. 

Metamorphic  slates  and  sandstones  were  seen  near  where  the  San 
Luis  Creek  passes  between  the  Buttes ;  and,  at  many  points  on  the 
plain  or  in  the  valley  about  San  Luis,  there  were  outcrops  of  rocks, 
and  sometimes  rocky  masses  of  several  acres  in  extent,  of  metamorphic 
sandstone,  sometimes  porpliyritic,  sometimes  quartzose,  and  occasion¬ 
ally  passing  into  serpentine.  The  Sierra  Santa  Lucia  was  climbed,  at 
a  point  about  due  northeast  of  the  town  of  San  Luis  Obispo.  Here 
there  are  foot-hills,  of  various  elevations,  intervening  between  the  main 
chain  or  ridge  and  the  valley ;  these  consist  mostly  of  serpentine  and 
other  metamorphic  rocks,  while  unaltered  stratified  sandstones  were 
seen  in  the  hills  west  of  the  San  Luis  Pass  road,  the  dip  and  strike 
being  very  variable,  the  strata  broken  up,  and  occasionally  a  little  meta¬ 
morphosed.  To  the  east  of  the  road,  in  the  line  of  the  section  on  page 
144,  the  rock  in  the  foot-hills  is  mostly  metamorphic,  with  large  quan¬ 
tities  of  serpentine,  and  the  same  serpentine  skirts  the  base  of  the  main 
chain.  On  ascending  the  principal  ridge,  however,  the  metamorphic 
rock  ceases,  and  the  slope  is  of  unaltered  strata,  chiefly  light-colored 
and  fine-grained  sandstones  and  slates,  sometimes  bituminous,  and,  at 
the  altitude  of  about  1800  feet,  a  stratum  of  impure  bituminous  lime¬ 
stone  occurs,  emitting  a  decidedly  fetid  odor  when  struck  with  the 
hammer.  These  rocks  probably  belong  to  the  bituminous  slate  series. 
The  slope  is  covered  with  soil  and  grassed  over,  although  steep,  the 
average  inclination  of  the  2000  feet  being  from  23°  to  26°,  while  por¬ 
tions  are  from  45°  to  47°.  On  nearing  the  top  of  the  ridge,  the  slates 
become  more  silicious,  as  if  metamorphosed,  and  the  soil  is  lighter, 
being  covered  with  manzanita  and  other  shrubby  plants,  conspicuous 
among  which  was  a  lupine  in  full  flower.  The  summit  consists  of  sev¬ 
eral  ridges,  more  or  less  nearly  parallel,  and  connected  by  transverse 
elevations,  which  appeared  to  be  the  result  of  extensive  erosions, 
effected  in  the  chain  after  its  upheaval.  The  strike  is,  in  the  main, 
parallel  with  that  of  the  chain,  but  varies  somewhat  in  the  different 


SOUTH  OF  TIIE  BAY  OF  MONTEREY. 


143 


ridges.  The  dip,  along  the  entire  southern  slope, is  to  the  north,  the 
angle  increasing  towards  the  summit,  and  near  the  central  axis  of  the 
range  it  is  generally  vertical.  The  northern  slope  of  the  chain  was  not 
examined ;  hut,  as  seen  from  a  distance,  the  dip  seemed  to  be  to  the 
south,  at  a  high  angle;  it  was  certainly  to  the  south  in  some  of  the 
ridges  on  that  side.  The  altitude  of  the  highest  point  reached  was 
found  to  be  2803  feet;  but,  at  the  distance  of  six  or  eight  miles  to  the 
southeast,  the  mountains  rise  to  a  height  of  about  3000  feet,  and  the 
same  was  true  at  a  distance  of  twelve  or  fourteen  miles  to  the  north¬ 


west. 

The  rock  on  these  summit  ridges  is  entirely  slate,  more  or  less  silici- 
tied.  In  the  vertical  strata,  the  laminae,  which  are  from  half  an  inch  to 
three  inches  thick,  are  very  brittle,  and  are  cleaved  and  weathered  at 
right-angles  to  the  stratification,  the  fine  weathered  lines  and  creases 
being  very  beautifully  marked,  large  surfaces  presenting  the  appear¬ 
ance  shown  in  the  annexed  diagram  (Fig.  20).  In  some  places  the 
rocks  are  semi-opaline  in  appearance  and  small 
pieces  of  chalcedony  are  abundant,  as  often  no¬ 
ticed  in  other  localities  where  the  slates  have  been 
subjected  to  this  silicification.  The  thin  soil  on 
these  silicious  rocks  produces  no  wild  oats,  nei¬ 
ther  does  the  clay  on  the  unaltered  slopes  of  the 


Fig.  20. 


LAMINATION  OF  SILICIFIED  BITU¬ 
MINOUS  SHALES. 


range. 


On  the  southern  side  of  the  range  this 


plant  formed  the  prevailing  herbage. 

A  section  across  the  Santa  Lucia  Range,  through  the  San  Luis’V  alley, 
and  across  the  chain  of  that  name,  to  the  Bay  of  San  Luis  Obispo,  is 
annexed  (Fig.  21). 

The  San  Luis  Pass,  across  the  Santa  Lucia  Range,  runs  nearly  north 
and  south,  and  the  summit  is  about  2000  feet  high.  The  road  passes  up  a 
canon,  on  the  west  side  of  which  was  much  serpentine  and  other  meta- 
morphic  rock.  The  strata  exhibited  in  the  pass,  after  leaving  the  al¬ 
tered  rocks  at  the  base,  are  slates,  occasionally  a  little  changed,  and 
having  a  north  or  northeastern  dip.  The  summit  is  of  sandstone,  and 
on  the  northern  slope,  where  there  were  fewer  outcrops  and  less  op¬ 
portunity  of  examining  the  strata,  they  appeared  a  good  deal  broken, 
and  dipping  to  the  southwest. 


Fig.  21.  S.  W. 

Section  from  San  Luis  Bay  to  Santa  Margarita  Yalley. 


144 


GEOLOGY  OF  THE  COAST  RANGES 


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The  Santa  Margarita  Yalley,  which 
lies  to  the  east  of  the  Santa  Lucia  Range, 
is  much  higher  than  the  San  Luis  Plain ; 
its  altitude  is  given  in  the  Pacific  Rail¬ 
road  Reports  at  1200  feet.  The  strata, 
so  far  as  seen,  were  much  disturbed  and 
often  metamorphosed,  and  generally 
dipped  to  the  southwest,  or  towards  the 
Santa  Lucia.  A  white  quartzose  sand¬ 
stone,  with  an  abundance  of  oysters  and 

pectens,  was  the  prevailing  rock,  until 

% 

the  party  left  this  valley  and  entered  that 
of  the  Salinas ;  it  decomposes  in  places 
into  a  very  dry  and  barren  soil.  This 
formation  was  observed  to  the  west  of 
Camp  27,  at  the  Atascadero  Ranch,  where 
it  contained  a  few  fossils,  supposed  to  be 
of  Pliocene  age.  To  the  east  of  the 
same  camp,  a  light  clay  slate  occurs,  with 
a  very  variable  strike  and  dip ;  this  was 
presumed  to  belong  to  the  bituminous 
slate  series.  These  slates  were,  in  places, 
much  silicified,  and  were  associated  with 
the  light,  infusorial  rock,  although  the 
relative  position  of  the  two  sets  of  strata 
was  not  determined. 

On  crossing  the  Santa  Lucia,  a  most 
marked  change  occurred  in  the  vegeta¬ 
tion  of  the  country,  not  so  much  an  ac¬ 
tual  change  of  species,  as  a  greater  pre¬ 
dominance  of  certain  conspicuous  forms, 
especially  of  the  arboreal.  The  number  of 
trees  was  greatly  increased  in  Santa  Mar¬ 
garita  Yalley,  oaks  and  pines  of  several 
species  became  abundant,  and  the  whole 
appearance  of  the  region  was  that  of  one 
where  more  rain  falls,  and  where  there 


SOUTH  OF  THE  BAY  OF  MONTEREY. 


145 


are  fewer  excessive  drouths  than  to  the  south  of  the  Santa  Lucia.  The 
Salinas  Valley  was  entered  by  following  down  the  Santa  Margarita 
Creek  to  the  old  mission  of  that  name.  Locally,  the  name  Santa  Mar¬ 
garita  is  given  to  the  valley,  for  an  indefinite  distance  down,  at  least  as 
far  as  the  Atascadero  Creek.  The  Salinas  River  heads  considerably  to 
the  south  of  this ;  hut  it  only  becomes  a  stream  of  importance  after  re¬ 
ceiving  the  waters  of  the  San  Antonio  and  Vascimiento  Rivers,  which 
drain  the  interior  of  the  rough  and  unknown  range  extending  down 
the  coast  from  Monterey  to  San  Luis  Obispo,  and  there  finding  its 
southern  extension  in  the  Santa  Lucia  Range,  to  which  it  is  generally 
considered  to  belong.  The  main  source  of  the  Salinas  proper  is  the  San 
Juan,  which  rises  in  the  lofty  mountains  to  the  west  of  the  Canada  de 
las  Uvas. 

The  Salinas  Valley  is  divided  by  the  San  Antonio  Hills  into  two 
portions.  These  hills  stretch  across  diagonally,  at  about  75  miles  from 
the  mouth  of  the  river,  and  the  region  above  is  a  sort  of  table-land  of 
low,  rolling  hills,,  while  below  there  is  a  valley  gradually  opening  out 
to  what,  in  California,  is  a  very  remarkable  width,  as  much  as  12  or 
15  miles  in  its  lower  extension.  The  party  passed  rapidly  down  this 
valley,  as,  owing  to  the  want  of  time  and  scarcity  of  feed  here,  the 
season  being  an  unusually  dry  one,  it  was  impossible  to  stop  at  more 
than  a  few  points  for  detailed  examination. 

The  valley  from  Paso  el  Roble  to  the  San  Antonio  River  is  occupied 
by  low  rounded  hills,  in  which  but  few  outcrops  of  rock  could  be  seen, 
the  soil  being  mostly  a  fertile  clay,  retentive  of  moisture,  well  adapted 
to  pasturage,  and  producing  an  abundance  of  wild  oats  and  clover. 
Rounded  hills  of  nearly  horizontally  stratified  gravel  were  seen  near 
the  river  in  places;  but  most  of  the  rock  observed  was  a  light-colored 
slate,  supposed  to  belong  to  the  bituminous  slate  series.  Between  the 
Atascadero  Ranch  and  the  Hascimiento  River  a  hot  spring  was  seen, 
of  which  the  temperature  was  100°,  and  the  character  similar  to  that  of 
the  other  springs  already  noticed.  It  has  considerable  local  reputation 
for  its  curative  effects. 

To  the  south-southwest  of  Camp  28,  at  the  Hascimiento  River,  the 
hills  were  examined  for  a  distance  of  six  or  eight  miles.  In  this  region 
there  is  an  immense  development  of  stratified  rocks,  having  a  strike  of 


geol.  vox,,  r. — 19 


146 


GEOLOGY  OF  THE  COAST  RANGES 


from  17.  45°  W.  to  IN’.  70°  W.  The  general  dip  of  the  mass  of  rock  is 
to  the  northeast,  although  some  portions  were  seen  inclined  in  the 
opposite  direction.  ^Nearest  the  valley  is  a  group  of  sandstone  strata, 
over  1000  feet  in  thickness,  generally  rather  soft,  and  in  some  places 
calcareous ;  some  of  the  strata  are  much  altered  by  the  infiltration  of 
calcareous  matter  into  them.  A  few  of  the  beds  are  fossiliferous,  and 
the  strike  of  these  is  from  i7.  45°  W.  to  17.  50°  W.,  or  nearly  parallel 
with  the  direction  of  the  ridges.  The  genus  Pecten  was  most  abun¬ 
dantly  represented  among  the  fossils,  especially  the  species  P.  Pabloen- 
sis ,  belonging  to  the  Miocene.  Beneath  these  strata,  and  apparently 
conformable  with  them,  were  heavy  masses  of  the  bituminous  slate, 
apparently  from  1500  to  2000  feet  thick,  having  generally  a  north¬ 
eastern  dip ;  but  there  was  one  large  wave  in  the  strata,  with  a  reversed 
dip,  or  to  the  southwest.  This  slate  formed  rounded  hills,  many  of 
them  of  considerable  height,  covered  with  a  clay  soil,  and  supporting  a 
vigorous  growth  of  wild  oats,  with  some  oaks,  chiefly  Q.  agrifolia.  The 
general  direction  of  these  ridges  was  17.  60°  W.  From  the  highest 
point  reached,  high  and  broken  mountains  were  seen  to  the  west  and 
southwest.  To  the  east,  and  at  a r  distance  of  six  or  eight  miles,  a 
“  mesa,”  or  table  mountain,  was  seen,  which  appeared  to  be  made  up 
of  horizontal  strata  left  in  the  position  by  denudation.  All  the- moun¬ 
tains  in  this  region  bear  marks  of  deep  and  long-continued  erosion,  and 
the  detailed  topography  is  exceedingly  complicated ;  no  map  gives  any 
idea  of  it.  The  names  of  important  water-courses  are  not  even  fixed,  or 
given  in  the  same  way  on  any  two  maps,  or  located  with  any  pretence 
to  accuracy.  All  the  region  to  the  northeast  of  the  San  Juan  River, 
and  between  that  and  the  Chelone,  seems  to  be  of  this  table-land, 
deeply  cut  by  ravines ;  of  these  there  arc  a  great  number  which  are 
nearly  parallel,  running  from  northeast  to  southwest,  and  in  the  rainy 
season  carrying  off  the  water  to  the  San  Juan. 

To  the  north  and  northeast  of  Camp  28,  on  the  17ascimiento,  the 
region  between  the  San  Antonio  and  !7ascimiento  Rivers  is  occupied 
by  hills,  some  of  them  rising  500  to  600  feet  above  the  river,  and  com¬ 
posed  entirely  of  horizontal  beds  of  gravel  and  sand.  This  gravel  is 
generally  not  very  coarse,  and  consists  of  sand  mixed  with  numerous 
fragments  of  the  bituminous  slates,  jasper,  and  other  metamorphic  rock, 


SOUTH  OF  THE  BAY  OF  MONTEREY. 


147 


and  with  a  few  pebbles  of  granite.  No 
fossils  could  be  found  in  these  beds,  al¬ 
though  they  were  carefully  sought  for. 
This  formation  occupies  the  space  between 
the  two  rivers,  and  extends  beyond  them 
in  places,  being  seen  also  on  the  east  bank 
of  the  Salinas,  forming,  at  many  points, 
high  bluffs. 

Farther  to  the  southwest  are  high  moun¬ 
tains,  containing  much  metamorphic  rock, 
as  was  ascertained  from  their  appearance, 
and  from  the  boulders  brought  down  in 
the  Arroyos.  The  horizontal  beds  no¬ 
ticed  above  extend  down  the  Salinas  for 
some  20  miles,  and  they  were  also  seen 
along  the  San  Antonio,  forming  high 
bluffs. 

Both  banks  of  the  Nascimiento  present 
a  fine  exhibition  of  terraces,  of  which 
those  on  the  north  are  the  best  defined, 
and  were  most  carefully  examined.  Above 
Camp  28,  and  nearer  the  hills,  there  are 
two  remarkably  well  defined  terraces,  be¬ 
sides  the  flats  elevated  a  few  feet  above 
the  river  on  each  side  of  the  wide  sandy 
bed.  The  lo’west  is  about  54  feet  above 
the  base,  two  measurements  a  mile  apart 
giving  52  and  55  feet;  its  surface  is  a 
nearly  level  plain,  varying  in  width  from 
a  few  rods  to  three-fourths  of  a  mile,  and 
very  plainly  marked  for  a  distance  of  four 
or  five  miles  down  the  river.  The  second 
terrace  is  65  feet  above  its  base,  and  is 
more  cut  by  Arroyos,  but  is  perfectly  well 
defined;  the  two,  as  seen  from  the  oppo¬ 
site  side  of  the  river,  their  tables  being 
covered  with  scattered  oaks,  present  a 


East  branch  of  the  Salinas  River,  b.  Sandy  bed  of  the  river,  c.  Bluff  on  south  side.  d.  Hills  of  horizontally  stratified  gravel  and  sand,  600  feet  high. 

e,  e,  e.  Terraces  near  the  Nascimiento.  Fossiliferous  sandstones,  g.  Folded  bituminous  slates. 


148 


GEOLOGY  OF  TIIE  COAST  RANGES 


very  regular  and  beautiful  appearance.  These  terraces  are  underlain 
by  the  horizontal  gravel-beds  on  the  lower  part  of  the  river;  but,  near 
the  hills,  they  extend  into  the  inclined  strata  of  sandstone. 

Below  our  camp,  near  Mr.  Thompson’s  house,  the  terraces  are  three 
in  number,  the  first  twenty  feet  high,  the  next  sixty  feet  above  the  first, 
and  the  third  one  hundred  and  seven  feet  above  the  second.  On  the 
first  one  stands  the  house ;  the  second  corresponds  with  the  first  one 
mentioned  above  as  occurring  above  the  camp,  and  it  can  be  traced 
from  the  hills  to  the  high  bluffs  of  horizontal  strata,  a  distance  of  about 
six  miles ;  the  third  and  highest  is  much  eroded,  and  forms  a  row  of 
hills  or  ridges,  of  uniform  height. 

At  this  place,  and  below  as  far  as  the  San  Antonio  Hills,  the  Salinas 
Valley  is  entirely  occupied  with  rounded  hills,  while  the  upper  part,  as 
far  to  the  southeast  as  the  eye  can  reach,  seems  one  wide  and  immense 
plain,  the  low  hills  in  the  valley  being  too  insignificant  to  be  marked 
features  in  a  distant  view. 

In  continuing  the  route  towards  Monterey,  from  the  Hascimiento,  the 
road  taken  led  up  the  San  Antonio  River  for  about  twenty  miles, 
to  Jolon,  a  few  miles  below  the  San  Antonio  Mission.  On  this  road 
the  bituminous  slate  was  struck  a  little  before  reaching  the  San  An¬ 
tonio  River.  The  rock  is  generally  a  cream-color,  but  is  sometimes 
almost  white.  It  is  very  fine-grained,  and  not  highly  bituminous, 
although  in  one  place  sufficiently  so  to  have  given  rise  to  a  flow  of  this 
material,  which  has  covered  the  road  with  the  hardened  asphaltum.  In 
some  localities  the  slates  are  considerably  silicified.  The  strata  have 
generally  a  dip  to  the  northeast,  but  not  uniformly  so.  There  were 
several  sections  examined,  all  of  which  indicated  an  immense  thickness 
for  this  formation. 

The  San  Antonio  and  Hascimiento  Rivers  run,  throughout  the  upper 
part  of  their  courses,  in  a  direction  opposite  to  that  of  the  Salinas,  or 
in  a  nearly  southeast  direction.  For  more  than  thirty  miles  they  are 
nearly  parallel,  and  about  five  or  six  miles  distant  from  each  other. 
The  region  between  them  is  occupied  by  high  ridges,  of  which  the  cul¬ 
minating  points  are  of  the  bituminous  slate,  having  a  general  direction 
of  northwest  and  southeast,  which  is  that  of  the  strike  of  the  rock.  But 
portions  of  this  rock  have  a  considerably  more  western  strike,  in  some 


SOUTH  OF  THE  BAY  OF  MONTEREY. 


149 


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cases  as  much  as  R.  65°  or  70°  W.  It  is  underlaid  by  sandstone,  which 
crops  out  on  the  south  edge  of  the  ridges,  and  also  extends  near  to  the 
Rascimicnto  River,  southwest  of  our  camp.  It  lies  against  the  heavier 
mountain  masses  behind,  and  is  very  extensively  metamorphosed. 

To  give  an  idea  of  the  structure  of  this  region,  a  section  is  appended 
(Fig.  23),  from  the  Rascimiento  to  the  San 
Antonio  River,  passing  through  the  Los  Ojitos 
Ranch  near  Jolon.  In  the  bituminous  slate 
ridge  (d)  there  appeared  to  be  three  folds;  but 
the  larger  mass  had  a  dip  of  over  40°  and  all 
of  over  20°.  The  thickness  of  the  formation 
was  estimated  at  from  2500  to  3000  feet.  This 
rock  is  frequently  silicitied  and  partially  al¬ 
tered;  but  no  metamorphism  was  observed 
among  the  sandstones  on  the  northeastern 
slope  of  the  ridge  (/).  Rear  the  canon  of  the 
Rascimiento  River  the  strata  are  much  broken, 
and  near  the  river,  at  cj ,  there  are  extensive 
lines  of  the  projecting  edges,  which  stand  out 
sometimes  to  the  height  of  300  to  400  feet, 
with  remarkably  grand  and  impressive  forms 
(see  wood-cut,  Fig.  24).  These  outcrops  ex¬ 
tend  alon<?  the  river  for  several  miles. 

With  the  beginning  of  the  metamorphic  rocks 
of  the  Santa  Lucia,  the  mountains  begin  to  as¬ 
sume  a  very  rugged  appearance,  the  slopes  be¬ 
coming  very  steep,  with  few  trees  and  much 
chaparral,  and  the  rocks  very  various  in  cha¬ 
racter.  One  rocky  slope  has  an  inclination,  as 
measured,  of  47°,  and  many  others  are  equally 
steep.  The  mountains  back  of  this  rise  to  the 
height  of  4000  feet  or  more,  and  appear  to  be 
almost  inaccessible.  The  rock,  as  far  as  could 
be  seen  from  the  ridge  ascended,  was  entirely 
metamorphic,  containing  much  serpentine,  the 
whole  mass  weathering  to  a  deep-brown  color. 


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150 


GEOLOGY  OF  THE  COAST  RANGES 


issues  from  the  heart  of  the  chain  there  are  an  enormous  quantity  of 
boulders,  many  of  several  (pubic  feet  in  size;  among  these  a  gieat  va¬ 
riety  of  rocks  were  noticed,  such  as  porphyry,  serpentine,  jaspery  slates, 
mica-slates,  gneiss,  quartz,  <fcc.  The  varieties  of  serpentine  were  the 


Fig.  24. 


SANDSTONE  OUTCROP,  NEAR  THE  NASCIMIENTO  RIVER. 


most  interesting,  there  being  many  specimens  which  showed  it  in  every 
stage  of  metamorpliism. 

Over  the  front  ridges,  where  the  slope  is  not  high,  especially  on  the 
bituminous  slate,  the  soil  supports  a  good  growth  of  oats,  and  there  are 
some  trees,  chiefly  oaks  and  pines.  The  drier  portions  of  the  surface 
are  covered  with  chaparral. 

Along  the  San  Antonio  River  and  extending  back  among  the  hills 
are  terraces,  well  marked  in  character;  they  were  not  measured. 

The  San  Antonio  Hills,  where  crossed,  were  entirely  of  bituminous 
slate,  the  strata  much  broken,  and  their  dip  and  strike  so  irregular 
that  it  was  impossible  to  make  out  what  the  average  might  be.  When 
crossed  on  the  Monterey  road,  the  highest  point  of  the  pass  is  perhaps 
1000  feet  above  the  Salinas  River,  and  the  most  elevated  portions  of 
the  adjacent  ridges  from  1500  to  1800  feet;  some  points  between  the 
pass  and  the  Salinas,  on  the  southeast,  are  perhaps  2000  feet  high. 

From  these  hills  to  the  Bay  of  Monterey,  a  distance  of  about  eighty 
miles,  the  Salinas  Valley  forms  an  uninterrupted  plain,  of  from  six  to 
ten  miles  wide,  entirely  without  water  during  the  summer,  excepting 


SOUTH  OF  THE  BAY  OF  MONTEREY. 


151 


what  flows  in  the  river,  as  the  streams  coming  down  from  the  moun¬ 
tains  on  either  hand  sink  on  reaching  the  valley.  The  surface  of  this 
plain  is  remarkably  uniform,  and  it  has  a  gentle  but  decided  and  regu¬ 
lar  slope  on  either  side  from  the  hills  to  the  river,  the  angle  being 
greatest  where  the  river  approaches  the  mountains  most  nearly,  as  it 
does  below  Soledad,  on  the  west  side.  Through  most  of  the  distance, 
especially  in  the  upper  part  of  the  valley,  the  Salinas  flows  in  many 
shallow  channels,  over  a  sandy  bed  from  half  a  mile  to  a  mile  and  a 
half  in  width,  which  is  more  or  less  fringed  with  trees,  and  consider¬ 
ably  below  the  level  of  the  plain,  generally  from  100  to  150  feet.  This 
descent  is  sometimes  in  one  bluff;  generally,  there  is  a  succession  of 
terraces.  At  Camp  30,  northwest  of  Espinosa,  there  were  three,  well- 
marked  ones.  These  terraces  form  a  noticeable  feature  of  the  valley, 
as  they  not  only  skirt  the  river,  but  extend  across  the  plain  in  various 
places,  marking  a  descent  in  the  valley  from  a  higher  to  a  lower  level, 
as  it  opens  out  to  the  northward. 

Near  Mission  Soledad,  below  where  the  Arroyo  Seco  joins  the  Sali¬ 
nas,  the  bluff  bank  is  at  the  base  of  the  foot-hills,  and  was  found  to 
be  from  125  to  150  feet  high,  the  steep  slope  being  covered  with  angu¬ 
lar  boulders  of  mica-slate.  These  terraces  extend  nearly  to  the  Bay  of 
Monterey.  The  soil  of  the  plain  is  very  dry ;  with  water  it  would  be 
extremely  fertile,  as  is  shown  at  Salinas,  and  at  a  few  other  points 
where  the  ground  has  been  cultivated.  The  conformation  of  the  valley 
and  the  dip  of  the  strata  on  the  western  slope  (the  eastern  side  was 
not  examined)  would  seem,  according  to  Professor  Brewer’s  opinion, 
to  indicate  that  artesian  wells  might  be  successfully  bored  in  many 
places,  although  water  would  not  probably  rise  to  the  surface  at  all 
points.  There  are  few  trees  in  the  plain,  excepting  the  belt  which 
skirts  the  river.  The  only  species  noticed  was  the  evergreen  oak  (Q. 
agrifolia ),  no  white  oaks  (robles)  being  seen  in  the  plain  after  passing 
the  San  Antonio  Range,  although  they  occur  on  the  hills.  The  fierce 
winds  which  blow  up  the  valley  would  probably  act  as  a  drawback  to 
the  cultivation  of  trees  on  the  plain.  The  forage  consisted  chiefly  of 
bunch-grass  and  pin-grass,  of  which  the  latter  is  by  far  the  most  valu¬ 
able. 

A  chain  of  hills — or  mountains,  as  they  might  be  called — commences 


152 


GEOLOGY  OF  THE  COAST  RANGES 


a  little  to  the  northwest  of  Monterey,  and  extends  in  a  nearly  southeast 
direction,  skirting  the  Santa  Lucia  Range  on  its  eastern  side.  This 
chain  is  about  seventy-five  miles  long  from  Monterey  to  where  the  Sa¬ 
linas  River  cuts  it.  In  the  Pacific  Railroad  Maps,  on  both  Parke’s  and 
Warren’s,  it  is  called  the  “  Sierra  de  Salinas;”  but  it  is  known  on  the 
spot  by  different  names  :  the  southeastern  end,  as  before  noticed,  is 
called  the  “  San  Antonio  Hills,”  while  the  northwestern  portion,  or, 
rather,  the  hills  lying  west  and  southwest  of  the  Soledad  Mission,  is 
known  as  the  “  Palo  Serito  Hills.”  This  chain  skirts  the  Salinas  Val¬ 
ley  and  the  Bay  of  Monterey  on  one  side,  and  is  separated  from  the 
Santa  Lucia  Range  by  the  valleys  of  the  Carmelo  and  San  Antonio 
Rivers  and  the  lateral  tributaries  of  the  Arroyo  Seco. 

The  hills  lying  between  the  Bay  of  Monterey  and  the  Carmelo  Val¬ 
ley  have  a  height  in  places  of  near  2000  feet;  the  central  part  of  the 
chain,  especially  the  mountains  between  the  Tularcitas  Ranch  in  the 
Carmelo  Valley,  and  the  Guadelupe,  Paraje  de  Sanchez,  and  Soledad 
Ranches  in  the  Salinas  Valley,  has  an  elevation  of  from  3000  to  3500 
feet,  while  the  southeastern  extremity  of  the  chain,  or  the  San  Antonio 
Hills,  seldom  rises  above  2500  feet. 

Both  ends  of  this  chain  are  almost  entirely  made  up  of  bituminous 
slate,  but  slightly  metamorphosed,  while  the  higher  central  portion 
contains  much  highly  altered  rock,  with  some  slate,  in  its  original  con¬ 
dition,  on  the  western  slope. 

As  has  already  been  remarked,  the  San  Antonio  Hills  were  only 
hastily  examined;  but,  as  far  as  seen,  they  were  found  to  be  made  up 
of  bituminous  slate,  which  is  there  developed  to  an  immense  thickness, 
the  strata  being  much  broken,  and  indeed  so  much  so,  that  no  definite 
knowledge  of  their  general  position  could  be  obtained. 

From  Mission  Soledad  to  the  Guadelupe  Ranch,  the  mountains  rise 
very  abruptly,  the  slopes  being  steep  and  covered  with  chaparral.  The 
rocks  on  the  east  side  are  nearly  all  metamorphic,  consisting  chiefly  of 
mica-slate,  in  places  interstratified  with  gneiss,  while  the  western  slope 
is  made  up  partly  of  metamorphic  rocks  and  partly  of  the  unaltered 
bituminous  slate.  The  boulders  seen  at  the  base  were  mostly  of  mica- 
slate.  The  ridge  was  ascended  from  Camp  31,  at  the  Guadelupe 
Ranch,  the  ascent  on  that  side  being  very  steep  for  2500  or  3000  feet, 


SOUTH  OF  TIIE  BAY  OF  MONTEREY. 


153 

and  the  rock  mica-slate,  with  a  general  northeast  dip,  and  traversed  by 
veins  of  quartz.  The  soil  was  found  to  he  light  and  dry,  supporting  a 
dense  growth  of  chaparral.  The  summit  was  several  miles  wide,  worn 
into  rounded  hills,  all  of  mica-slate,  the  highest  points  being  about 
3500  feet  above  the  sea,  and  covered  with  wild  oats  and  scattered 
patches  of  chaparral,  with  here  and  there  a  few  oaks.  On  the  western 
side  the  descent  was  much  more  gradual.  Several  beds  of  highly  crys¬ 
tallized  limestone  were  noticed  in  ascending  on  the  eastern  side,  at  an 
elevation  of  from  2500  to  2800  feet.  This  limestone,  as  well  as  the 
mica-slate,  contained  many  minute  crystals  of  graphite,  which  were 
most  perfect  in  the  calcareous  rock ;  these  crystals  were  usually  arranged 
along  certain  lines  in  the  limestone,  so  as  to  give  it  a  stratified  appear¬ 
ance,  and,  in  the  weathered  portions  of  the  rock,  marks  of  the  original 
planes  of  deposition  could  be  traced  in  the  highly  crystalline  material. 
This  rock  had  been  “  prospected”  for  silver  wherever  the  graphite  was 
abundant,  as  had  also  the  metamorphic  slates  under  the  same  circum¬ 
stances. 

The  west  slope  of  these  hills  was  seen  on  a  trip  up  the  Carmelo  V al¬ 
ley  and  through  the  Arroyo  Seco.  It  consists  of  the  white  bituminous 
slate,  traversed  by  bands  of  mica-slate  and  gneiss.  Professor  Brewer 
thinks  there  is  no  doubt  that  these  rocks  have  resulted  from  meta¬ 
morphic  action  on  the  bituminous  slates,  the  carbon  of  the  bitumen 
appearing  in  the  altered  rocks  as  graphite.  Ho  traces  of  an  eruptive 
axis  were  observed  in  this  chain,  and  there  was  everywhere  a  complete 
conformability  between  the  altered  and  unaltered  rocks  as  to  dip  and 
strike. 

The  chain  of  the  Palo  Scrito  Hills  trends  more  westerly  as  we  leave 
the  Guadelupe  and  Buenavista  Ranches,  going  towards  Monterey. 
Where  examined  near  that  town,  and  between  it  and  the  Mission  Car¬ 
melo,  the  bituminous  slate  was  found  to  be  entirely  unaltered,  and  to 
dip  northeast  at  a  low  angle,  forming  a  range  of  hills  with  rounded  out¬ 
lines.  Hear  Monterey  it  is  very  light  in  texture,  and  contains  some 
fossils,  the  first  obtained  from  this  rock,  although  it  had  been  closely 
examined  at  many  points,  for  a  distance  of  300  miles  along  its  outcrop. 
The  only  good  locality  found  was  one  about  two  miles  southeast  of  the 
town,  at  some  old  quarries,  where  a  sufficient  number  of  species  were 

OEOL.  VOL.  I. — 20 


154 


GEOLOGY  OF  THE  COAST  RANGES 


obtained  to  enable  ns  to  fix  the  age  of  this  extensively  developed  for¬ 
mation  ;  it  belongs  to  the  Miocene  Tertiary. 

The  rock  is  soft  and  can  easily  be  cut  with  an  axe,  yet  it  is  sufficiently 
durable,  in  that  climate,  to  be  used  for  building  purposes ;  walls  laid 
50  or  60  years  ago  still  show  the  marks  of  the  tools  used  in  dressing 
the  stone.  The  Mission  Carmelo  is  built  of  this  material,  and  has 
withstood  exposure  well.  Both  sandstone  and  limestone,  more  or  less 
impregnated  with  bitumen,  occur  in  the  slate.  The  sandstone  is  in 
thick  strata,  and  has  been  used  for  a  building  material.  The  slate 
crosses  the  Carmelo  River  and  forms  high  hills,  best  seen  in  the  “  Po- 
trero  de  San  Carlos”  Ranch,  about  three  miles  from  the  sea,  where  it 
rises  to  the  height  of  about  a  thousand  feet,  the  strata  having  a  general 
dip  to  the  northeast,  and  being  in  places  more  or  less  silicified.  After 
ascending  the  Carmelo  some  six  or  eight  miles,  this  formation  is  found 
to  be  entirely  confined  to  the  northeastern  side  of  that  stream. 

Extending  east  from  Monterey  to  the  Salinas  Valley,  at  the  Buena- 
vista  Ranch,  a  group  of  rocks,  newer  in  age  than  the  bituminous  slate, 
is  seen  resting  on  the  north  flank  of  the  Palo  Serito  Hills ;  they  were 
examined  on  the  Toro  and  Laguna  Seca  Ranches.  The  rocks  of  this 
formation  are  sandstones  and  conglomerates,  and,  in  one  place,  a 
limited  outcrop  of  argillaceous  limestone  was  seen.  The  strata  have 
a  thickness  of  several  hundred  feet,  and  some  beds-  are  quite  fossili- 
ferous.  The  following  species  were  collected  here : 

Neptunjea  recurva,  Modiola  capax, 

Modiola  recta,  Arca  canalis. 

These  sandstones  and  conglomerates  are  either  horizontal  ,  or  inclined 
at  an  angle  of  less  than  20°  to  the  north  and  northeast;  but  nearer  the 
main  chain  of  the  hills  they  are  somewhat  broken,  and  dip  at  a  higher 
angle.  They  have  been  much  denuded  since  their  elevation,  and  a 
number  of  good  sections  can  be  obtained  in  the  Canada  of  El  Toro. 
Some  portions  of  this  rock  disintegrate  into  a  soil  of  sufficient  firmness 
to  support  a  tolerable  growth  of  wild  oats ;  but  it  is  generally  much 
inferior  to  that  produced  by  the  bituminous  slate,  and  large  portions  of 
the  region  underlaid  by  it  are  covered  by  a  dry  sand,  which  is  over- 


SOUTH  OF  THU  BAY  OF  MONTEREY. 


155 


grown  with  thickets  of  low  chaparral,  and  is  of  little  value  for  agricul¬ 
ture.  These  rocks  appear  to  belong  to  the  upper  division  of  the  Mio¬ 
cene  Tertiary;  but  a  more  careful  investigation  is  necessary,  to  deter¬ 
mine  exactly  the  relations  of  the  group  to  the  underlying  beds  of  bitu¬ 
minous  slate.  A  map  of  the  vicinity  of  Monterey,  on  a  large  scale, 
has  been  begun  ;  but  it  is  not  yet  completed. 

To  obtain  further  information  with  regard  to  the  rough  and  unknown 
region  lying  between  the  Salinas  Valley  and  the  Ocean,  an  excursion 
was  made  up  the  Carmelo  Valley  to  the  Arroyo  Seco.  In  passing  up 
this  valley,  intrusions  of  granite  are  seen  occurring  near  the  coast, 
which  will  be  noticed  farther  on.  For  six  or  eight  miles,  the  bitumi¬ 
nous  slate  is  found  on  both  sides  of  the  river,  forming  rounded  hills  of 
from  1200  to  1800  feet  in  height.  Beyond  this,  the  river,  for  a  few 
miles,  follows  a  break  between  the  sandstones  and  the  bituminous 
slates,  the  left  bank  being  occupied  by  the  sandstones,  and  metamor- 
phic  patches  begin  to  be  seen.  FTear  the  river  are  heavy  beds  of  sand 
and  detritus,  chiefly  derived  from  the  decomposition  and  wear  of  mica- 
slate.  At  the  distance  of  flfteen  or  eighteen  miles  from  its  mouth,  the 
valley  assumes  the  character  of  a  canon,  and  leads  back  into  the  heart 
of  the  mountain  with  a  more  southerly  direction.  It  was  not  possible 
to  follow  it  any  farther,  but  a  route  was  taken  which  led  diagonally 
across  from  the  Carmelo  Valley  to  that  of  the  Arroyo  Seco.  On  this 
line  of  travel  rounded  hills  of  bituminous  slate  were  crossed,  covered 
with  wild  oats  and  affording  good  pasturage.  In  passing  through  the 
valleys  between  these  hills,  frequent  localities  of  sandstone,  slate,  and 
metamorphic  rock  were  noticed,  the  strata  being  much  broken,  and 
the  sandstones  generally  on  the  south  side  of  the  road  and  the  slate  on 
the  north.  Kear  the  Arroyo  Seco,  however,  the  sandstones  retreat, 
and  the  slates  pass  farther  up  into  the  San  Lucia  chain.  The  only  fos¬ 
sils  seen  were  some  fragments  of  bone  in  a  boulder  near  Finch’s  Ranch, 

and  a  single  vertebra  (cetacean  ?). 

* 

On  approaching  the  Arroyo  Seco,  the  strata  are  not  only  much 
broken,  but  are  often  contorted,  as  if  they  had  been  subjected  to  dis¬ 
turbance  and  compression  while  still  plastic.  They  appear  to  have 
been  caught  in  and  folded  between  the  two  axes  or  lines  of  upheaval  of 
the  Palo  Scrito  and  Santa  Lucia  chains.  The  Arroyo  Seco  heads  far 


156 


GEOLOGY  OF  THE  COAST  RANGES 


back  in  the  Santa  Lucia  chain,  breaks  through  its  ridges  and  again 
through  those  of  the  Palo  Scrito  Hills,  at  nearly  right-angles  to  their 
direction,  and  issues  forth  into  the  Salinas  Plain  at  Soledad  Mission, 
not  as  a  creek,  but  as  a  dry,  wide,  sandy  bed  of  one.  The  “  Arroyo 
Seco”  proper  is  the  dry  bed  of  the  creek,  or  of  that  portion  of  it  which 
lies  in  the  Palo  Scrito  Hills,  and  where  the  stream  sinks ;  but  above 
this  it  is  a  large  and  permanent  flow  of  water;  this  is,  however,  in  a 
region  perhaps  as  little  known  or  visited  as  any  part  of  California  wrest 
of  the  Sierra. 

In  an  excursion  into  this  wild  region,  our  party  struck  the  river  at 
fourteen  miles  from  Soledad,  and  pushed  up  the  canon  several  miles 
into  the  Santa  Lucia  chain.  At  the  point  where  the  canon  was  entered, 
near  Robinson’s  Ranch,  the  slate  lies  at  every  conceivable  angle  of  dip 
and  strike,  but  the  great  masses  have  a  general  inclination  to  the  north¬ 
east,  and  are  in  places  considerably  metamorphosed.  The  canon  ap¬ 
pears  to  occupy  a  break  in  the  strata,  in  which  were  large  masses  of 
rock  highly  inclined,  and  which  had  suffered  much  compression  and 
distortion.  Some  of  these  folds  are  on  a  grand  scale,  and  very  interest¬ 
ing,  as  they  are  so  well  laid  open  for  examination  in  the  sections  which 
the  stream  has  cut  through  them.  Among  the  various  exhibitions  of 
contortion  and  flexure  in  these  strata,  the  annexed  example  (Fig.  25) 
may  be  selected;  it  was  taken  about  two  miles  above  Robinson’s  Ranch, 
and  represents  a  length  of  from  800  to  1000  feet,  and  a  vertical  eleva¬ 
tion  of  about  300.  Many  others,  on  an  equally  grand  scale,  were  ob- 


Fig.  25. 


FLEXURES  IN  THE  BITUMINOUS  SLATE  ON  THE  ARROYO  SECO. 


served  in  this  vicinity.  Such  contortions  are  most  abundant  in  the 
canon;  in  the  great  masses  of  the  hills,  the  dip  of  the  slate  is  much 
more  regular,  the  formation  overlying  the  sandstone  with  a  general  dip 
to  the  northeast.  Immense  mountain  masses  were  seen  in  this  position. 


SOUTH  OF  TIIE  BAY  OF  MONTEREY. 


157 


Farther  up  the  canon  occur  large  masses  of  sandstone,  much  broken, 
but  still  having  a  general  northeasterly  dip.  Not  unfrequently  the  slate 
forms  ridges  displaying  great  folds  and  disturbances,  and  heavy  bodies 
of  strata  have  an  inclination  in  the  opposite  direction  from  that  of  the 
sandstone  strata  in  the  vicinity;  this  may  be  seen  represented  on  the 
annexed  section  (Fig.  26),  in  which  a  and  b  represent  two  hills  of  sand¬ 
stone,  one  before  and  the  other  behind  the  ridge  of  slates,  and  having 


Fig.  26. 

s.  w.  N.  E. 


a  northeast  dip,  while  the  great  mass  of  slates  between  them  dips  to 
the  southwest. 

The  Santa  Lucia  chain  has  already  been  spoken  of  several  times,  and 
its  structure  near  San  Luis  Obispo  given  in  section.  It  remains  to  add 
what  little  farther  information  has  been  obtained  with  regard  to  its 
northern  extension. 

Beginning  at  Point  Carmelo,  the  Santa  Lucia  rises  suddenly,  and 
extends  along  the  coast  in  a  range  unbroken  by  any  considerable  de¬ 
pression,  and  not  crossed  by  any  road,  for  a  distance  of  fully  one  hundred 
and  ten  miles,  namely,  to  the  San  Luis  Obispo  Pass.  For  at  least  ninety 
miles  of  this  distance,  the  chain  consists  of  the  most  rugged  mountains, 
and  is  entirely  unexplored;  the  Coast  Survey  have  made  no  attempt  to 
carry  their  triangulation  along  its  craggy  ridges,  as  has  been  done  both 
to  the  north  and  south.  A  few  small  ranches  exist  along  the  coast,  for 
thirty  miles  south  of  Monterey,  and  are  reached  by  a  path  along  the 
shore.  Three  or  four  trails  are  said  to  cross  the  chain,  but  little  is 
definitely  known  in  regard  to  them,  except  that  they  are  very  difiicult 
and  very  little  used. 

Wherever  this  chain  was  seen  from  the  lesser  heights,  at  various 
points  in  the  Palo  Scrito  Hills,  it  appeared  as  a  succession  of  very  sharp 
ridges  and  peaks,  furrowed  by  deep  carious,  all  the  slopes  being  steep 
and  mostly  covered  with  dense  chaparral,  while  the  whole  region  is 


158 


GEOLOGY  OF  THE  COAST  RANGES 


exceedingly  dry  during  the  summer  months.  Many  peaks  were  seen 
which  were  estimated  at  from  4000  to  4500  feet  in  height,  and  some 
probably  reach  5000.  Owing  to  the  rugged  character  of  the  mountains, 
the  scarcity  of  wiater,  the  extreme  density  of  the  chaparral,  and  the 
number  and  ferocity  of  the  wild  beasts,  which  have  full  possession  of 
the  region,  it  would  he  a  peculiarly  difficult  one  to  explore,  perhaps 
more  so  than  any  other  portion  of  the  State  of  equal  area. 

Only  the  most  eastern  of  the  ridges  were  visited,  and  these  only  at  a 
few  points.  Granite  exists  in  large  masses  in  the  interior  of  the  range ; 
it  occurs  at  Point  Carmelo  and  extends  along  the  coast  to  El  Sur, 
twenty  miles  from  Carmelo  Bay,  and  possibly  much  farther.  Various 
authorities,  among  the  few  mountaineers  who  know  anything  about  the 
chain,  speak  of  large  quantities  of  very  decomposable  granite  as  exist¬ 
ing  at  various  points  in  the  mountains ;  and  boulders  in  the  Rascimi- 
ento,  San*  Antonio,  and  Arroyo  Seco  Rivers  show  that  this  rock  is 
abundant  near  their  sources.  Resting  on  the  granite  is  a  sandstone  of 
Tertiary  age  (probably  Miocene),  and  very  extensively  metamorphosed. 
Every  variety  of  form  of  the  metamorphic  sandstone,  so  often  spoken 
of  as  occurring  in  the  Coast  Ranges,  is  seen  here,  especially  serpentine. 
Gold  has  been  found  at  various  places,  although  nowhere  in  large  quan¬ 
tities.  Placers  are  or  were  worked  during  a  portion  of  the  year  near 
San  Antonio,  and  the  precious  metal  has  been  found  at  other  places. 
Small  quantities  of  silver  ore,  argentiferous  galena,  have  been  found  at 
Arroyo  Seco,  and  have  caused,  at  times,  much  excitement  and  the  ex¬ 
penditure  of  several  thousand  dollars,  without  any  prospect  of  getting 
back  a  single  one  of  them.  Copper  stains  are  also  abundant  in  the 
metamorphic  rock ;  but  nothing  is  known  of  the  existence  of  workable 
veins. 

The  greatest  width  of  this  mountain  region  is  about  twenty-five 
miles,  and  the  average  about  eighteen ;  thus  there  is  here  an  area  of 
not  less  than  1500  square  miles,  entirely  unexplored,  and  which  will 
probably  remain  so  for  a  long  period  to  come. 


SOUTH  OF  THE  BAY  OF  MONTEREY. 


159 


Section  III. — The  Gayilan  Range. 

The  Gavilan  chain  lies  between  the  Salinas  Valley  on  the  southwest 
and  the  San  Juan  and  San  Benito  Valleys  on  the  northeast;  it  extends 
from  the  Pajaro  River  on  the  northwest,  an'd  may  be  considered  as  ter¬ 
minating  at  the  San  Lorenzo  on  the  southeast.  On  the  northwest,  it 
is  connected  with  the  Santa  Cruz  Mountains  by  the  hills  near  the  Pa¬ 
jaro  River,  and  from  this  end  it  has  all  the  appearance  of  a  distinct  and 
independent  range ;  but,  as  we  follow  it  to  the  south,  we  find  it  gradu¬ 
ally  becoming  merged  in  the  Monte  Diablo  Range  on  the  east,  being 
separated  from  it  by  the  very  narrow  valley,  or  canon,  of  the  San  Be¬ 
nito.  The  region  around  the  southeastern  extension  of  this  chain  re¬ 
mains  almost  entirely  unexplored,  especially  the  portion  of  it  between 
San  Lorenzo  and  Chelone  Creeks.  As  defined  above,  the  Gavilan 
chain  has  a  length  of  about  seventy-five  miles,  and  a  breadth  of  ten. 
The  peak  at  the  north  end  of  the  chain,  called  the  “  Gavilan  Peak,” 
was  the  only  one  measured ;  it  is  2932  feet  above  Camp  38,  near  San 
Juan,  and  about  3381  feet  above  the  sea.  The  dominating  point  of  the 
chain,  about  thirty-five  miles  southeast  of  the  Gavilan  Peak,  was  esti¬ 
mated  at  3800  feet ;  it  is  called  Mount  Chelone. 

In  crossing  the  Gavilan  Range  from  the  Salinas  to  San  Juan,  on  the 
Monterey  road,  metamorphic  limestone  is  met  with  on  the  southern 
side,  the  only  other  rock  seen  being  unaltered  sandstone,  with  southern 
dip,  the  strata  considerably  broken,  and  the  hills  scarcely  over  1500 
feet  high.  But  on  crossing  the  range,  in  the  same  direction,  a  few 
miles  farther  to  the  east,  and  getting  a  section  through  Gavilan  Peak, 
nearly  the  whole  series  of  rocks  passed  over  was  found  to  be  metamor¬ 
phic.  The  unaltered  sandstones  extend  along  the  north  side,  near  the 
San  Juan  Valley,  forming  the  San  Juan  Hills,  which  extend  to  the  Pa¬ 
jaro  River;  in  these  hills  the  strata  are  very  heavy-bedded,  and  have  a 
dip  everywhere  to  the  south.  The  materials  of  which  they  are  made  up 
are  often  coarse,  and  sometimes  large  enough  to  form  a  conglomerate, 
among  the  pebbles  of  which  jasper  and  other  metamorphic  rocks  pre¬ 
dominate.  Portions  of  the  formation  are  fossiliferous ;  but  all  the 
shells  found  were  in  such  a  bad  state  of  preservation  that  little  or 


160 


GEOLOGY  OF  THE  COAST  RANGES 


nothing  could  be  made  of  them.  There  is  not  much  doubt,  however, 
that  these  rocks  form  a  part  of  the  Miocene  Tertiary,  so  extensively 
developed  in  the  Coast  Ranges.  Some  bones  were  obtained  from  the 
sandstone  near  our  camp  at  San  Juan,  but  they  have  not  yet  been  ex¬ 
amined. 

These  rocks  become  metamorphic  near  the  trail  from  the  Canon  San 
Juan  to  Natividad  Ranch.  Along  this  trail  serpentine  was  seen  ;  but  it 
was  not  discovered  in  the  section  extending  through  the  peak.  Meta¬ 
morphic  limestone  exists  abundantly  in  the  region  ;  it  may  be  seen  in 
a  round,  dome-shaped  hill,  800  or  900  feet  high,  near  Mr.  Johnston’s, 
on  the  Natividad  Ranch;  this  elevation  is  a  conspicuous  object  in  ap¬ 
proaching  the  chain  from  the  north. 

The  same  limestone  forms  the  culminating  points  of  this  part  of  the 
range,  namely,  the  Gavilan  Peak  proper,  and  those  adjacent  to  it. 
These  peaks,  so  conspicuous  from  either  side,  form  a  sharp  ridge, 
several  miles  long,  extending  from  east  to  west,  its  general  direction 
from  the  summit  being  R".  78°  E. — S.  78°  W.,  the  ridge  curving  and 
cutting  the  chain  diagonally.  This  culminating  ridge  was  examined  at 
its  highest  point,  and  also  three  or  four  miles  west  of  this;  in  both 

places  the  crest  was  of  metamorphic  limestone,  with  a  high  southern 

» 

dip,  75°  to  80°,  and  in  some  places  vertical.  To  the  northward  were 
metamorphic  rocks,  quartz,  mica-slate,  gneissoid  granite,  and  beds 
of  semi-crystalline  limestone,  the  whole  having  a  dip  to  the  south  of 
from  40°  to  80°.  The  strata  on  the  southern  slope  of  the  crest  were 
not  passed  over,  but  appeared  to  dip  in  the  same  direction.  The  gneis¬ 
soid  granite  in  the  centre  of  the  chain  was  in  some  places  very  hard, 
in  others  very  decomposable,  forming  a  dry,  sandy  soil,  covered  with  a 
low  chaparral,  or  chamisal.  The  whole  range  is  much  denuded,  and 
worn  into  deep  and  precipitous  canons,  which  do  not  coincide  in  direc¬ 
tion  with  the  strike  of  the  strata. 


Section  IY. — The  Vicinity  of  the  Bay  of  Monterey. 

The  geology  of  the  region  around  Monterey  and  Carmelo  Bay  is  of 
peculiar  interest,  owing  to  the  presence  of  granitic  and  metamorphic 


SOUTH  OF  THE  BAY  OF  MONTEREY.  161 

rocks  in  close  proximity  to  unaltered  strata,  and  the  favorable  oppor¬ 
tunities  for  studying  the  relations  of  these  formations,  afforded  by 
the  exposures  in  the  cliffs  along  the  Ocean,  will  always  render  this  an 
attractive  locality  for  the  geologist. 

The  country  to  the  east  of  Monterey  is  sandy  and  low,  being  a  con¬ 
tinuation  of  the  Salinas  plains,  and  the  town  itself  is  built  at  the  point 
where  this  sandy  plain  ceases,  and  where  the  granite  comes  down  to 
the  sea,  abutting  against  the  bituminous  slates,  which  also  just  touch 
the  bay  at  this  point. 

The  granite  occupies  the  promontory,  extending  from  Point  Pinos  to 
Cypress  Point,  and  is  bounded  on  the  land  side  by  a  line  drawn  from 
Monterey  to  the  Pescadero  Punch,  on  Carmelo  Bay.  It  also  occurs  in 
several  detached  patches  along  the  shore  of  the  bay  and  a  short  dis¬ 
tance  in  the  interior;  at  Point  Carmelo  it  forms  the  entire  shore  line 
again,  and  extends  down  the  coast  for  an  unknown  distance.  It  was 
followed  in  this  direction  for  eight  miles,  but  is  said  to  form  the  shore 
at  El  Sur,  and  it  probably  extends  still  farther,  as  has  already  been 
noticed,  in  speaking  of  the  Santa  Lucia  Range,  of  which  this  granite 
mass  forms  a  part. 

This  granite  is  coarse-grained,  and  contains  crystals  of  feldspar  (or- 
thoclase),  often  two  inches  in  length,  and  sometimes  as  much  as  four. 
It  is  frequently  traversed  by  quartzose  or  feldspathic  veins,  and  some¬ 
times  by  those  of  granite  of  a  different  character  from  the  principal 
mass.  This  rock  has  been  quarried  at  bWint  Pinos,  near  Monterey, 
and  at  Point  Carmelo,  or  Point  Lobos ;  at  the  last  locality  a  large 
amount  of  it  has  been  got  out,  some  of  it  used,  and  the  remainder  left 
lying  on  the  spot.  Where  the  granite  is  free  from  sulphuret  of  iron,  it 
is  of  excellent  quality,  dresses  easily  and  with  a  handsome  surface,  and 
pieces  which  have  been  lying  here  for  six  years  or  more  remain  per¬ 
fectly  sound  and  retain  their  natural  bright  color.  Some  portions  which 
contained  pyrites  have  become  discolored,  and  partly  disintegrated;  but 
the  larger  part  seems  to  be  good.  The  facilities  for  quarrying  and 
loading  are  remarkably  fine,  and  the  quarry  will  probably  come  into 
use  again.  The  rock  consists  of  white  orthoclase  and  quartz,  with  fine 
scales  of  black  mica  disseminated  through  the  mass.  A  sand  of  the 
most  dazzling  whiteness,  apparently  formed  by  the  action  of  the  surf 

GEOL.  VOL.  I. — 21 


1G2 


GEOLOGY  OF  THE  COAST  RANGES 


on  this  granite,  has  accumulated  in  places  along  the  beach;  of  this  an 
enormous  pile  lies  near  Cypress  Point,  and  another  near  the  Pescadero 
Ranch.  The  material  seems  suited  to  the  manufacture  of  glass,  at 
least  of  the  coarser  kinds,  and  should  he  tried  for  the  finer  qualities, 
as  the  locality  is  convenient  and  the  quantity  practically  inexhaustible. 

This  granite  is  flanked  by  sandstone  of  Tertiary  age  (Miocene),  and 
good  opportunities  were  had  of  examining  the  junction  of  the  two  for¬ 
mations  in  various  places.  At  the  Point  Lobos  quarry  just  noticed,  the 
sandstone  dips  from  tlie  granite,  at  an  angle  of  35°  immediately  at  the 
junction;  but  its  inclination  rapidly  decreases,  and  is  considerably  less 
at  a  short  distance  from  the  line  of  contact.  Both  rocks  are  consider¬ 
ably  altered,  for  a  distance  of  about  twenty  feet  from  the  junction;  the 
sandstone  is  softened  and  disintegrated,  and  the  granite  discolored. 
At  the  Pescadero  ranch-house,  the  contact  of  these  two  formations  may 
also  be  examined;  here  the  dip  of  the  sandstone  is  towards  the  granite, 

as  shown  in  the  annexed  section 
(Fig.  27).  The  metamorpbism  of 
these  formations  may  be  observed 
here,  extending  for  a  distance  of 
twenty  feet  or  thereabouts,  and 
affecting  both  rocks,  so  that  it 
would  not  be  easy  to  say  where 
is  the  precise  line  of  junction; 
on  both  sides  of  it  tlie  rocks  are 
softened,  discolored,  and  more 
or  less  disintegrated.  At  other  points  the  same,  or  similar,  phenomena 
were  observed. 

At  a  small  outcrop  of  granite  directly  west  of  the  Mission,  the  sand¬ 
stones  are  highly  metamorphosed,  for  a  distance  of  about  three  hun¬ 
dred  feet,  along  the  north  side  of  the  junction  of  the  two  formations. 
Through  nearly  the  whole  of  that  width,  the  granite  is  so  soft  that  it 
can  easily  be  crushed  in  the  hand ;  but  this  change  in  structure  is  not 
more  particularly  marked  in  the  immediate  vicinity  of  the  line  of  con¬ 
tact,  than  it  is  at  some  distance  from  it.  The  altered  strata  of  sand¬ 
stone  dip  away  from  the  granite  for  a  few  feet,  and  then  portions  be¬ 
come  exceedingly  hard,  and  almost  basaltic  in  appearance,  although 


Fig.  27. 


JUNCTION  or  GRANITE  AND  SANDSTONE  NEAR 
PESCADERO. 

a.  Sandstone,  dipping  south,  h.  Granite,  e. 
Conglomerate,  i.  Junction;  the  shaded  part  in¬ 
dicating  the  extent  of  the  metamorphism.  d.  Ar¬ 
royo. 


SOUTH  OF  THE  BAY  OF  MONTEREY. 


1G3 


the  planes  of  stratification  are  still  evident.  Portions  of  the  strata  are 
much  twisted  and  contorted,  and  cindery  in  appearance.  Although 
there  cannot  he  much  doubt  of  the  proximity  of  volcanic  rocks  beneath 
the  surface  at  this  locality,  there  did  not  seem  to  be  any  visible;  por¬ 
tions  of  the  metamorphic  strata  might,  however,  be  readily  taken  for 
eruptive,  if  they  had  been  seen  out  of  their  connection  with  the  same 
rock  in  a  less  advanced  stage  of  metamorphism. 

The  most  interesting  locality  of  all  in  this  vicinity,  for  studying 
metamorphic  action,  is  along  the  shore  of  the  bay,  a  little  to  the  south¬ 
east  of  the  Pescadero  ranch-house,  where  a  long  point  projects  into  the 
water,  giving  a  fine  chance  to  study  the  relations  of  the  formations, 
which  are  well  exposed  on  all  sides.  This  mass  of  altered  and  eruptive 
rock  is  entirely  inclosed  in  the  sandstone,  and  has  no  granite  near  it, 
thus  showing  clearly  that  it  is  not  the  presence  of  this  latter  rock, 
which  has  effected  such  great  changes  in  the  sedimentary  strata  at 
various  places  around  the  bay.  The  cliffs  on  the  north  side  of  the  pro¬ 
jecting  point  rise  from  sixty  to  eighty,  and  in  some  places  as  much  as 
a  hundred,  feet  above  the  sea;  the  rock  on  this  side  is  in  places  a  hard, 
compact,  dark-colored  basaltic  material,  breaking  up  into  prismatic 
fragments,  apparently  an  eruptive  mass  originally,  but  now  itself  par¬ 
tially  altered  by  the  same  causes  which  have  effected  so  extensive  a 
metamorphism  of  the  adjacent  sedimentary  strata. 

This  partial  metamorphism  of  the  igneous  mass  exhibits  itself  espe¬ 
cially  on  its  borders,  and,  as  one  result,  it  is  quite  impossible  to  say 
where  one  formation  commences  and  the  other  ends.  Near  the  edge 
of  the  water,  the  eruptive  rock  is  seen  to  rest  on  a  bed  of  a  brecciated 
conglomerate,  made  up  of  an  accumulation  of  the  fragments  of  the 
sedimentary  beds  through  which  the  volcanic  material  lias  forced  its 
way.  On  the  south  side  of  the  point,  the  results  of  metamorphic  ac¬ 
tion  are  beautifully  displayed  along  the  broken  edges  of  the  strata,  as 
seen  in  the  gradual  falling  oft*  of  the  cliffs  to  the  level  of  the  water.  In 
passing  from  the  entirely  unaltered  beds  of  sandstone  towards  the 
eruptive  mass,  the  first  evidence  of  change  is  detected  in  the  reddening 
of  the  strata;  then  the  lines  of  stratification  become  obliterated,  which 
feature  is  particularly  marked  in  the  vicinity  of  the  cross-veins  of 
various  mineral  substances  by  which  the  rocks  are  intersected;  next, 


164 


GEOLOGY  OF  THE  COAST  RANGES 


the  mass  becomes  scoriaceous,  or  is  filled  with  amygdaloidal  cavities, 
growing  more  and  more  dark-colored,  until  it  finally  passes  into  what 
appears  to  he  an  unmistakably  eruptive  rock,  although  it  would  he 
impossible  to  say  where  the  line  separating  the  two  formations  should 
be  drawn. 


minerals  have  been  formed  in  the  fissures  caused  by  the  uplifting  of 
the  intrusive  mass  through  the  sedimentary  rocks ;  these  are  chiefly 
seen  on  the  southern  side  of  the  point.  The  material  with  which  they 
are  filled  is  principally  carbonate  of  lime,  having  a  radiated  structure ; 
silica,  in  the  form  of  crystallized  quartz,  also  occurs,  as  also  some  ser¬ 
pentine.  Wide  spaces  of  the  metamorphic  mass  are  sometimes  filled 
with  a  network  of  small  veins  of  these  various  minerals,  and  the  large 
veins  have  many  fragments  of  the  wall-rock  scattered  through  them, 
so  as  to  form,  in  some  places,  a  regular  breccia.  Hardly  any  traces  of 
metalliferous  ores  are  seen  in  these  veins,  and  no  zeolitic  minerals  were 
detected ;  indeed,  the  volcanic  masses,  and  the  sedimentary  beds  which 
have  been  metamorphosed  by  them,  are,  throughout  the  State,  remark¬ 
ably  destitute  of  interesting  associated  minerals,  such  as  the  zeolites. 
In  several  respects  the  appearance  of  the  rocks  just  noticed  strikingly 
resembles  that  presented  on  Lake  Superior,  at  many  points  along  the 
line  of  contact  of  the  trap  'and  sandstone,  showing  that  the  physical 
conditions  were  very  nearly  the  same,  during  one  of  the  earliest  geo¬ 
logical  periods,  when  the  Lake  Superior  volcanic  beds  were  poured 
forth,  as  those  which  prevailed  at  the  very  recent  epoch  when  the  Pa¬ 
cific  coast  was  the  scene  of  the  display  of  these  forces.  A  set  of  speci¬ 
mens,  from  the  Silurian  sandstones  and  the  accompanying  volcanic 
rocks  of  nearly  contemporaneous  age,  might  be  made  up  on  the  shores 
of  Lake  Superior,  which  would  hardly  be  distinguished  from  another 
collection  which  could  be  gathered  around  Carmelo  Bay,  where  the 
eruptive  intrusions  and  subsequent  metamorphic  changes  have  all  taken 
place  since  the  epoch  of  the  Miocene  Tertiary. 

A  map  of  the  vicinity  of  Monterey,  including  Carmelo  Bay  and  ex¬ 
tending  east  to  the  Salinas  Elver,  on  a  scale  of  two  miles  to  the  inch, 
has  been  partly  prepared  by  the  Survey,  on  which  the  details  of  the 
geology  will  be  given.  This  map  will  be  completed  and  published,  in 


SOUTH  OF  THE  BAY  OF  MONTEREY. 


165 


the  volume  of  maps  and  sections,  forming  a  portion  of  our  Final  Report. 
There  are  many  things  about  Carmelo  Bay  to  make  it  an  attractive 
region;  and  we  may  confidently  predict  that  it  will,  at  some  future  time, 
become  a  place  of  resort,  if  not  for  the  fashionable  world,  at  least  for 
those  who  would  combine  with  the  enjoyment  of  the  ocean  breezes,  the 
pursuit  of  geological,  botanical,  or  zoological  studies  ;  in  each  of  these 
departments  there  is  much  that  is  interesting,  and  some  things  that  are 
peculiar,  to  be  found  between  Cypress  and  Carmelo  Points  and  in  the 
adjacent  region. 

Extending  along  on  the  east  side  of  the  Bay  of  Monterey,  nearly  the 
same  rocks  are  found  which  have  already  been  noticed  as  occurring  to 
the  south.  From  San  Juan  to  the  Pajaro  Valley,  near  Watsonville, 
low  hills  of  sandstone  occur,  with  a  gentle  dip  to  the  south.  The  Pa¬ 
jaro  Valley  is  an  inclosed  basin  through  which  the  river  of  the  same 
name  finds  its  way ;  the  bottom-land  is  some  three  miles  wide  and  six 
or  eight  long,  of  extraordinary  fertility,  and  under  high  cultivation. 
This  valley,  as  well  as  the  region  near  Santa  Cruz,  does  not  suffer  so 
severely  from  drouth  as  the  country  farther  east,  being  watered  by 
the  fogs  and  dews  from  the  sea.  In  consequence  of  this,  trees  are 
more  numerous,  and  grain  and  fruit  crops  reliable.  The  rocks  are  the 
bituminous  slates,  nearly  horizontal  in  position.  Terraces  were  ob¬ 
served  on  the  north  side  of  the  Pajaro  Valley,  and  also  in  the  vicinity 
of  Santa  Cruz,  especially  to  the  east  of  the  city.  There  are  two  which 
are  well  marked  and  extend  for  several  miles ;  of  these,  the  first  forms 
a  bluff  bank  along  the  sea-shore,  64  feet  high,  near  Camp  44,  one  mile 
southeast  of  the  town,  and  extends  back  in  a  nearly  level  table  from 
half  a  mile  to  two  miles  in  width,  although  somewhat  cut  up  by  ar- 
royos ;  on  this  terrace  the  town  of  Santa  Cruz  stands.  The  second  is 
199  feet  above  the  first,  or  268  feet  above  high  tide;  it  was  examined 
in  several  places,  the  best  locality  for  that  purpose  being  behind  the 
Mission  Church,  near  the  town.  This  table  is  not  as  wide  as  the  other; 
but  is  still  a  marked  feature  in  the  landscape. 

In  the  vicinity  of  Santa  Cruz  the  rock  is  the  bituminous  slate,  some 
portions  of  which  are  quite  light  and  soft,  while  others  are  more  sili- 
cious;  in  one  case,  a  stratum  of  six  or  eight  feet  in  thickness  was 
noticed  as  being  entirely  silicified.  The  strata  are  nearly  horizontal, 


16G 


GEOLOGY  OF  THE  COAST  RANGES 


or  have  only  a  slight  dip  to  the  south  on  the  shore,  hut  are  apparently 
conformable  with  the  broken  and  highly  inclined  beds  in  the  mass  of 
mountains  to  the  northeast  of  the  town,  as  if  the  upheaving  force  had 
not  extended  entirely  to  the  coast  in  this  direction. 

An  extensive  outcrop  of  metamorphic  and  highly  crystalline  lime¬ 
stone  occurs  on  the  ranch  “  Canada  del  Rincon,”  about  two  miles  north¬ 
west  of  the  town.  It  was  not  easy  to  determine  its  position  with  posi¬ 
tive  certainty;  hut  it  appeared  to  have  a  dip  to  the  north  of  from  65° 
to  68°.  The  rock  is  usually  pure  white,  but  portions  of  it  are  brown ; 
this  color  is  discharged  by  burning,  leaving  an  almost  perfectly  white 
lime.  The  discoloration  is  probably  due  to  bitumen,  as  the  rock  emits 
the  odor  of  this  substance  when  struck.  It  is  extensively  burned  for 
lime  by  Messrs.  Jordan  and  Davis,  whose  kilns  produce  about  500  bar¬ 
rels  per  month.  The  rock  is  quarried  in  a  canon  near  by,  and  trans¬ 
ported  to  the  kilns  on  a  tram-road,  the  loaded  cars  descending  by 
gravity.  All  the  necessary  facilities  for  producing  good  and  cheap 
lime  are  found  here,  and  this  concern  supplied  the  entire  consumption 
of  San  Francisco  and  the  adjacent  region. 


CHAPTER  VI. 

THE  COAST  RANGES  FROM  THE  VICINITY"  OF  LOS  ANGELES,  SOUTH. 

Section  I. — Preliminary  Remarks. 

In  the  preceding  chapters  we  have  given  a  general  idea  of  the  geolo¬ 
gical  structure  of  the  Coast  Ranges  in  the  vicinity  of  the  Bay  of  San 
Francisco  and  to  the  south  of  it,  as  far  as  the  Sierra  Santa  Susanna  and 
the  Plain  of  San  Fernando.  It  now  remains,  to  complete  what  we  have 
to  say  before  passing  to  the  Sierra  Nevada,  to  take  up  the  southern 
extension  of  the  Coast  Mountains,  the  portion  yet  remaining  to  be 
described  being  the  ranges  from  the  Santa  Monica  and  San  Gabriel 
chains  southward  to  the  border  of  the  State. 

Thus  far,  in  our  summary  of  the  geology,  we  have  had  no  difficulty 


SOUTH  OF  LOS  ANGELES. 


1G7 


in  distinguishing  the  Coast  Ranges  from  the  Sierra;  hut  we  have  now 
arrived  at  a  point  where  it  is  necessary  either  to  draw  an  artificial  line 
separating  one  system  of  mountains  from  the  other,  or  else  to  establish 
some  criterion  by  which  they  shall  be  geologically  distinguished,  as  it 
is  evident,  from  a  simple  inspection  of  the  map,  that  below  the  San 
Gabriel  Range  we  have  no  longer  any  guide  to  the  settlement  of  this 
question  in  the  topographical  character  of  the  country.  Without  stop¬ 
ping  here  to  go  into  a  full  investigation  of  the  matter,  we  would  simply 
say  that  we  consider  all  those  chains  or  ranges  of  mountains  to  belong 
to  the  Coast  Ranges,  which  have  been  uplifted  since  the  deposition  of 
the  Cretaceous  formation ;  those,  on  the  other  hand,  which  were  ele¬ 
vated  before  the  epoch  of  the  Cretaceous  are  reckoned  as  belonging  to 
the  Sierra  Nevada. 

In  passing  from  north  to  south  along  the  foot-hills  of  the  Sierra,  we 
find,  at  numerous  points,  the  marine  Tertiary  or  Cretaceous,  or  both, 
resting  in  a  horizontal  position  on  the  upturned  edges  of  the  slates  and 
metamorphic  rocks  of  the  auriferous  series.  As  we  skirt  the  base  of 
the  Sierra,  however,  in  the  region  where  this  chain  turns  to  the  west, 
towards  Fort  Tdjon,  we  pass  at  once  from  undisturbed  Tertiary  to 
strata  of  the  same  age  which  are  elevated  at  a  high  angle,  and,  in  so 
doing,  we  leave  the  system  of  the  Sierra  and  pass  over  to  that  of  the 
Coast  Ranges.  This  change  takes  place  about  midway  between  the 
Tdjon  Pass  and  the  Canada  de  las  Ilvas;  but  no  break  in  the  moun¬ 
tain  ranges  indicates  this  transition.  The  great  lines  of  disturbance 
are  so  closely  connected  with  each  other  in  direction,  and  they  have 
been  so  affected  in  this  vicinity  by  the  existence  of  secondary  ones, 
that  the  topography  of  the  country  does  not  reveal  the  geological  facts, 
which  not  the  less  do  really  exist. 

Starting  then  from  a  point  a  little  to  the  east  of  the  Canada  de  las 
Uvas,  and  drawing  a  line  which  shall  leave  on  the  west  all  the  moun¬ 
tains  elevated  since  the  deposition  of  the  Cretaceous,  and  on  the  east 
those  which  have  not  been  disturbed  since  that  epoch,  we  find  that, 
according  to  the  present  state  of  our  knowledge,  this  line  will  pass  to 
the  east  of  the  San  Gabriel  Range,  through  the  Cajon  Pass,  to  the  east 
of  the  Temescal  Range  and  on  the  south  of  the  Santa  Anna,  striking 
the  Ocean  in  the  vicinity  of  San  Luis  Rey,  which  is  the  most  southerly 


168 


GEOLOGY  OF  THE  COAST  RANGES 


point  to  which  the  Coast  Range  system  lias  been  traced.  The  masses 
of  San  Bernardino  and  San  Jacinto  are  included  in  the  Sierra  Nevada, 
which  runs  south  and  occupies  the  peninsula  of  Lower  California,  the 
Coast  Range  system  not  having  an  existence  in  that  region. 

The  principal  group  of  mountains  included  in  the  portion  of  the 
Coast  Ranges  now  under  consideration  are,  the  Sierra  Santa  Monica, 
the  San  Gabriel,  the  Temescal,  and  the  Santa  Anna  Ranges.  These 
will  he  taken  up  in  this  order,  and  the  result  of  our  very  hasty  exami¬ 
nations  in  this  region  given. 


Section  II. — Sierra  Santa  Monica. 

The  range  of  mountains,  called  the  Sierra  Santa  Monica,  extends 
along  the  coast,  west  of  Los  Angeles,  beginning  to  the  west  of  the 
Cahuenga  Pass,  and  terminating  on  the  Pacific,  in  a  bold  headland, 
called  Point  Mogu.  There  are  no  roads,  or  passes  with  travelled  trails, 
across  this  range,  the  main  channel  of  land  communication  between 
Santa  Barbara  and  Los  Angeles  being  to  the  north  of  it,  through  the 
Cahuenga  Pass.  The  length  of  the  chain  is  about  thirty-six  miles,  and 
its  width  from  north  to  south  about  six. 

Near  the  east  end  of  the  range,  at  Hancock’s  Canon,  about  nine 
miles  west  of  Los  Angeles,  a  dark  silicious  slate,  or  slaty  sandstone,  is 
exposed  along  the  south  flank  of  the  mountains.  It  has  a  very  con¬ 
siderable  thickness,  and  dips  away  from  the  centre  of  the  chain,  or 
towards  the  south,  and  is  succeeded  on  the  north  by  the  mass  of  granite 
forming  the  axis  of  this  group  of  elevations,  and  from  which  the  rocks 
dip  on  each  side  (see  section  on  page  121,  across  the  Santa  Monica  and 
Santa  Susanna  Mountains). 

The  slates  run  about  N.  70°  W. — S.  70°  E.,  the  trend  of  the  strata 
being  a  little  more  to  the  north  than  the  direction  of  the  range  itself. 
The  granite  axis  is  here  perhaps  a  mile  in  width,  and  near  it  the  slates 
are  much  hardened  and  metamorphosed,  and  penetrated  by  small  veins 
of  quartz.  The  same  formation  occurs  on  the  north  side  of  the  intru¬ 
sive  mass  and  also  dips  away  from  it,  displaying  exactly  the  same  phe¬ 
nomena  of  metamorphism  as  on  the  south  flank,  so  that  we  have  here 


1G9 


SOUTH  OF  LOS  ANGELES. 

one  of  tlie  best  possible  examples  of  a  truly  anticlinal  range  of  moun¬ 
tains,  with  a  central  core  of  granite,  having  all  the  appearance  of  an 
intrusive  rock  which  has  burst  asunder  and  elevated  the  slaty  strata, 
producing  a  highly  metamorphic  condition  of  the  sedimentary  beds 
along  the  lines  of  contact  of  the  granitic  mass;  these  chemical  changes, 
as  well  as  the  mechanical  displacement  of  the  strata,  become  less  and 
less  conspicuous  as  we  recede  in  either  direction  from  the  intrusive 
central  core. 

The  rock  in  place  is  almost  everywhere  concealed  by  a  heavy  cover¬ 
ing  of  granitic  detritus,  which  is  formed  by  this  easily  decomposing 
rock,  the  harder  portion  being  left,  like  boulders,  on  the  surface.  The 
slates,  on  the  north  side  of  the  range,  pass  into  sandstones,  which  ex¬ 
tend  down  to  the  San  Fernando  Plain.  The  whole  chain  is  deeply  fur¬ 
rowed  by  canons,  which  run  at  right-angles  to  its  general  direction, 
and  give  it  the  appearance,  as  seen  from  the  high  points  of  the  San  Ga¬ 
briel  Range  to  the  east,  of  being  made  up  of  a  series  of  parallel  north 
and  south  ranges.  The  denudation  has,  in  some  places,  left  the  granite 
in  the  form  of  long  ridges,  running  north  and  south,  on  the  summit  of 
which  there  is  hardly  more  than  room  for  a  trail,  while  the  sides  slope 
in  each  direction  from  the  crest  of  the  ridge  with  a  very  steep  descent. 

The  Santa  Monica  chain  was  also  examined  from  our  camp  at  the 
mouth  of  the  Santa  Monica  Canon,  about  fifteen  miles  from  Los  An¬ 
geles.  This  canon  runs  far  up  into  the  range,  and  a  passable  wagon- 
road  might  easily  be  made  through  it  across  the  range. 

This  canon  is  finely  terraced  at  its  mouth,  where  it  meets  the  Ocean. 
There  are  four  well-marked  benches.  The  first  and  second  of  these 
are  close  to  the  beach,  and  respectively  15  and  25  feet  high ;  the  third 
is  325  feet  behind  the  second,  and  17  feet  above  it;  the  fourth  192  feet 
back  of  the  third,  and  91  feet  above  it,  making  the  total  height  from 
the  sea  to  the  summit  of  the  highest  terrace,  148  feet. 

An  interesting  section  was  observed  on  the  sea-shore,  a  little  above 
the  mouth  of  this  canon.  A  valley  seems  once  to  have  existed  here 
and  afterwards  to  have  become  filled  with  stratified  sedimentary  mate¬ 
rial,  as  represented  in  the  annexed  section  (Fig.  28). 

The  cliff*,  which  rises  nearly  perpendicularly  from  the  ocean-beach, 
to  the  height  of  about  175  feet,  is  made  up  of  horizontally  stratified 
a  eol.  yol.  i. — 22 


170 


GEOLOGY  OF  THE  COAST  RANGES 


detritus,  consisting  of  coarse  and  angular  materials,  chiefly  fragments 
of  the  bituminous  and  silicious  slates  of  the  vicinity.  In  this  terrace 
or  bed  of  detritus,  there  was  once  a  valley,  or  ravine,  extending  down 


Fig.  28. 


to  the  present  level  of  the  Ocean,  and  560  feet  wide,  as  now  shown  in 
the  section  exposed  in  the  bluff  which  has  been  formed  by  the  action 
of  the  sea.  The  terrace  or  plain  of  detrital  materials  is  spread  out  at 
the  base  of  the  Santa  Monica,  having  a  width  of  three  or  four  miles, 
and  the  canon  of  the  same  name  is  cut  in  it  to  a  depth  of  about  150 
feet.  The  curious  feature  in  this  ancient  valley  is,  that,  after  its  forma¬ 
tion,  it  became  filled  up  again  with  detrital  material,  perfectly  dis¬ 
tinctly  stratified,  and  everywhere  inclining  at  an  angle  of  23°,  as  repre¬ 
sented  in  the  wood-cut.  The  material  is  a  fine  sandy  loam,  with  a  few 
small,  rounded  pebbles,  and  quite  different  in  appearance  from  the 
horizontally  stratified  detritus  on  each  side.  This  is  an  interesting  sec¬ 
tion,  as  showing  the  possibility  of  the  deposition  of  a  large  body  of 
stratified  material  with  perfect  regularity  at  as  high  an  angle  as  twenty- 
three  degrees.  What  the  extent  of  this  mass  of  inclined  strata  back 
into  the  interior  may  be,  it  was  impossible  to  ascertain. 

At  the  entrance  of  the  Santa  Monica  Canon  into  the  mountains,  there 
are  heavy  masses  of  conglomerate,  very  coarse,  made  up  of  quartz  peb¬ 
bles  mixed  irregularly  with  fragments  of  slate  and  sandstone,  and  desti¬ 
tute  of  any  regular  stratification,  although  very  thoroughly  consolidated. 
This  formation  shows  itself  in  nearly  vertical  cliffs,  fully  200  feet  high, 
along  the  mouth  of  the  canon.  It  is  probably  a  late  Tertiary  forma¬ 
tion,  and  of  the  same  age  as  the  conglomerate  which  occurs  near  Los 
Angeles,  in  the  low  hills  to  the  south  of  the  town. 

Beyond  this  conglomerate  to  the  north,  for  the  distance  of  a  mile  up 
the  canon,  the  rock  is  a  coarse,  qnartzose  sandstone,  of  a  brownish- 


SOUTH  OF  LOS  ANGELES. 


171 


yellow  color,  and  much  broken  up,  so  that  the  planes  of  stratification 
could  hardly  be  made  out.  This  is  succeeded  by  a  dark-colored, 
slightly  bituminous  slate,  in  which  no  trace  of  fossils  could  be  discov¬ 
ered.  This  rock  dips  to  the  south,  until  wo  reach  the  centre  of  the 
chain,  where  there  is  a  break  and  a  sudden  reversal  of  the  strata,  which, 
for  the  rest  of  the  Way  across  the  canon,  dip  to  the  north,  forming  an 
anticlinal  axis,  although  there  is  no  intrusive  rock  visible  in  this  sec¬ 
tion.  The  slate,  however,  is  much  metamorphosed  in  the  central  part 
of  the  range,  assuming  the  appearance  of  a  trappean  rock  and  break¬ 
ing  up  into  small  prismatic  fragments.  Proceeding  north,  we  find  this 
metamorphosed  rock  gradually  reassuming  its  original  appearance  of  a 
soft,  unaltered  slate,  with  almost  exactly  the  same  succession  of  changes 
which  was  observed  in  Hancock’s  Canon,  where  the  intrusive  granite 
has  come  to  the  surface  and  occupies  the  centre  of  the  chain.  The 
bottom  of  the  canon  is  covered  with  a  thick  deposit  of  fragments  of 
blue  and  black  slate,  with  little  soil,  but  supporting  a  dense  growth 
of  evergreen  oaks.  It  is  from  the  canons  of  the  Santa  Monica  Range 
that  Los  Angeles  is  chiefly  supplied  with  fuel. 

A  sufficient  number  of  fossils  were  discovered  in  the  unaltered  sand¬ 
stones  of  the  Santa  Monica  Range  to  fix  their  age  as  that  of  the  Miocene 
Tertiary. 

The  following  species  were  noticed  by  Mr.  Gabb  in  the  collections 
made  in  this  chain,  and  chiefly  in  Hancock’s  Canon : 


Neverita  Kecluziana, 
Turritella  Ocoyana, 
Trociiita  costellata, 


Cerithidea  sacrata, 
Cardita  subtenta, 
Mytilus  edulis. 


Section  III. — San  Gabriel  Range,  and  the  Vicinity  of  Los  Angeles. 

The  San  Gabriel  Range,  as  we  denominate  it,  is  a  vast  mass  of 
mountains,  extending  from  the  Cajon  Pass  on  the  east,  and  joining  with 
the  Santa  Monica  and  Santa  Susanna  Ranges  on  the  west.  It  is  fully 
60  miles  long,  and  from  20  to  25  broad  from  north  to  south,  forming  an 
extensive  region  of  lofty  and  rugged  mountains,  of  the  interior  topo- 


172 


GEOLOGY  OF  THE  COAST  RANGES 


graphy  of  which  nothing  is  yet  accurately  known.  Even  the  name  of 
its  dominating  peak,  San  Antonio,  has  not  yet  found  its  way  on  to  any 
map.  We  have  given  to  the  whole  range  the  name  of  San  Gabriel,  in 
preference  to  that  of  San  Antonio,  as  the  latter  has  been  already  applied 
to  another  chain.  San  Gabriel  is  the  designation  of  the  principal  canon 
by  which  the  chain  is  traversed,  and  of  the  only  stream  of  any  size 
which  heads  in  it. 

The  San  Gabriel  Range  has  heretofore  been  very  differently  classed 
and  connected  with  the  other  mountain  ranges  of  this  region,  by  va¬ 
rious  writers  on  the  geology  and  topography  of  this  portion  of  the 
State.  By  some,  it  is  considered  as  a  continuation  of  Mount  San  Ber¬ 
nardino,  and  called  by  that  name;  by  others,  it  has  been  made  a  part 
of  a  separate  chain,  extending  from  near  the  San  Emidio  Canon  down 
through  the  Peninsula  of  Lower  California.  As,  however,  we  know 
that  the  San  Gabriel  Mountains  have  been  elevated  since  the  deposi¬ 
tion  of  the  Cretaceous,  and  as  there  are  strong  reasons  for  believing,  on 
the  other  hand,  that  Mount  San  Bernardino  belongs  to  the  system  of 
the  Sierra  Nevada,  it  is  impossible  to  include  these  two  ranges  under 
one  name,  although  they  are  topographically  closely  connected  with 
each  other,  just  as  are  the  Coast  Ranges  and  the  Sierra  near  Fort 
T£jon. 

The  mass  of  the  San  Gabriel  Range  is  of  granitic  and  highly  meta- 
morphic  rocks,  the  granite  being  very  extensively  developed  on  the 
south  side  of  the  chain,  and  appearing  to  be  a  part  of  the  same  up¬ 
heaval  with  that  of  the  central  portion  of  the  Sierra  Santa  Monica. 
Two  high  points  of  granite,  without  names,  nearly  north  of  Los  An¬ 
geles,  were  measured  and  found  to  be  4760  and  5346  feet  above  the  sea. 
In  this  portion  of  ' the  range,  the  rock  is  exclusively  granite,  except  at 
the  base  of  the  mountain,  where  Tertiary  sandstones  are  seen  in  the 
arroyos  which  have  cut  down  through  the  heavy  masses  of  Post-Ter¬ 
tiary  detritus,  which  lie  piled  up  against  the  flanks  of  the  range,  to  a 
height  in  places  exceeding  1000  feet. 

The  San  Gabriel  Canon  is  said  to  extend  nearly  through  this  chain, 
in  a  north  and  south  direction.  We  followed  it  up  a  few  miles  and 
found  its  sides  very  precipitous,  and  the  rocks  all  highly  metamorpliic. 
Boulders  of  slate,  hornblende-rock,  and  gneiss,  were  strewn  in  the 


SOUTH  OF  LOS  ANGELES. 


173 


greatest  profusion  along  the  bottom  of  the  canon,  which  during  the 
rainy  season  is  hardly  wider  than  the  bed  of  the  river.  Just  after  our 
arrival  at  the  entrance  of  the  canon,  and  as  we  were  preparing  to  ex¬ 
plore  it  more  fully,-  we  were  entirely  cut  off  from  all  access  to  it  by  the 
sudden  rise  of  the  San  Gabriel  River,  after  a  three  days’  rain,  which 
completely  filled  the  gorge,  drowning  several  persons.  Specimens  of 
copper  ore  were  shown  us,  brought  from  some  distance  up  the  canon ; 
some  silver  ore  has  also  been  found,  and  much  prospecting  done  for 
this  metal,  a  few  miles  from  the  mouth  of  the  gorge.  If  we  are  cor¬ 
rect  in  referring  these  metamorphic  rocks  to  the  Cretaceous  epoch,  it 
is  not  probable  that  any  very  valuable  veins  of  copper  or  silver  will  be 
found  here.  There  is  more  or  less  washing  for  gold  going  on,  during 
the  winter,  in  and  about  the  bed  of  the  creek,  as  also  along  the  base  of 
the  range  at  various  points,  especially  near  the  entrance  of  the  Santa 
Anita  Canon.  It  was  not  easy  to  ascertain  whether  these  washings  were 
very  profitable;  but  it  was  inferred,  from  all  that  was  seen,  that  they 
were  not  particularly  so. 

The  highest  point  of  the  San  Gabriel  Mountains  is  known  as  San 
Antonio ;  it  is  towards  the  east  end  of  the  range,  and  is  a  conspicuous 
point  from  all  the  region  to  the  south.  We  estimated  it  to  be  about 
6500  feet  high,  although  not  near  enough  to  give  a  very  reliable  guess 
at  its  altitude.  The  southern  edge  of  the  chain  was  explored  by  us, 
for  some  six  or  eight  miles  to  the  east  of  the  mouth  of  the  San  Gabriel 


Canon.  There  are  immense  masses  of  sandstone  and  conglomerate, 
probably  of  Tertiary  age,  along  the  foot  of  the  range,  which  have,  in 
places,  been  completely  overturned,  so  as  to  dip  to  the  north,  or  to¬ 
wards  the  centre  of  the  chain.  These  rocks  are  penetrated  by  dykes 
of  granite  in  all  directions,  and  most  irregularly  and  peculiarly  meta¬ 
morphosed.  The  whole  of  this  side  of  the  chain  shows  most  extensive 
disturbances  and  powerful  metamorphic  action  to  have  taken  place,  at 
a  very  recent  geological  epoch,  or  after  the  deposition  of  the  Miocene 
Tertiary. 

At  a  few  miles’  distance  to  the  south  of  the  San  Gabriel  Range,  and 
parallel  with  it,  is  a  low  range  of  hills,  which  are  made  up  of  sand¬ 
stones  and  dark  argillaceous  shales;  these  appear  in  places  to  have 
been  thoroughly  broken  up,  and  recemented  by  sand  forced  in  between 


174 


GEOLOGY  OF  THE  COAST  RANGES 


the  fragments,  forming  a  singular  breccia.  Other  portions  of  the  range 
have  evidently  been  the  seat  of  extensive  hot  springs  in  former  times, 
and  have  undergone  a  thorough  process  of  silicification.  Large  masses 
of  strata  consist  of  fragments  of  sandstone,  each  suf rounded  by  a  coat¬ 
ing  of  chalcedony,  presenting  truly  a  remarkable  appearance.  Every¬ 
thing  would  indicate  the  proximity  of  volcanic  tires  to  this  range  of 
hills  ;  but  no  rock  which  could  be  with  certainty  classed  as  eruptive 
was  seen  here. 

In  the  vicinity  of  Los  Angeles  the  rocks  exposed  are  chiefly  argilla¬ 
ceous,  shaly  sandstones,  with  dark-colored  shales  interstratified ;  these 
rocks  are  highly  bituminous,  and  have  a  general  southerly  dip.  In  the 
Arroyo  Seco,  which  comes  into  the  Los  Angeles  River  from  the  north¬ 
east,  these  strata  are  well  displayed ;  they  there  dip  to  the  south  at  an 
angle  of  from  25°  to  45°.  The  bitumen  is  seen  oozing  out,  in  many 
places,  from  the  slialy  beds,  sometimes  forming  what  are  generally 
known  as  “  tar-springs;”  this  material  hardens,  on  exposure,  into 
“  brea,”  or  asplialtum. 

The  heights  bordering  the  Los  Angeles  River,  two  miles  north  of  the 
city,  are  made  up  of  this  argillaceous  sandstone,  with  occasional  peb¬ 
bles  of  quartz  disseminated  through  it.  The  strike  of  these  beds  is 
about  R".  80°  W.,  and  their  dip  to  the  south  at  a  high  angle.  Over  300 
feet  in  thickness  of  this  formation  is  there  exposed.  A  little  farther 
south  the  same  strata  are  turned  up  at  as  high  an  angle  as  70°.  In 
some  places  these  shales  and  sandstones  are  capped  by  horizontal 
deposits  of  coarse  conglomerate,  made  up  of  pebbles  of  granite,  quartz, 
and  hornblende-rock,  and  not  firmly  consolidated.  This  is  evidently  a 
very  modern  formation,  although  elevated  at  least  100  to  125  feet  above 
the  plain.  There  is  a  thickness  of  25  to  30  feet  of  this  conglomerate 
exposed. 

About  seven  miles  due  west  of  Los  Angeles  is  the  most  important 
of  the  numerous  tar-springs  seen  in  this  vicinity.  It  is  from  here  that 
most  of  the  asplialtum  used  in  the  town  is  obtained.  Over  a  space  of 
fifteen  or  twenty  acres,  the  bituminous  material  (which  when  seen  by 
us,  in  the  winter,  had  exactly  the  consistency  and  color  of  tar)  was  ooz¬ 
ing  out  of  the  ground  at  numerous  points.  It  hardens  on  exposure  to 
the  air,  and  becomes  mixed  with  sand  and  dust  blown  into  it,  and  is 


SOUTH  OF  LOS  ANGELES. 


175 


then  known  as  “brea.”  The  holes  through  which  the  bitumen  comes 
to  the  surface  are  not  large,  few  being  more  than  three  or  four  inches 
in  diameter.  On  removing  the  tarry  substance  from  the  holes,  by  re¬ 
peatedly  inserting  a  stick,  the  empty  cavity  was  very  slowly  filled  up 
again.  At  one  place  there  was  a  pit  several  yards  square,  and  six  or 
eight  feet  deep,  from  which  the  tar  had  been  taken  ;  but  it  was  filled 

0 

with  water,  at  the  time  of  our  visit,  in  consequence  of  late  heavy  rains. 
The  brea  is  used  almost  exclusively  for  covering  roofs  at  Los  Angeles, 
selling  (in  1861)  at  the  springs  for  $1  per  barrel,  the  purchaser  collect¬ 
ing  it  himself,  which  is  done  by  digging  a  pit  two  or  three  feet  deep 
by  the  side  of  one  of  the  holes  from  which  the  tar  is  issuing,  and  letting 
it  fill  up.  A  very  large  amount  of  the  hardened  asphaltum,  mixed 
with  sand  and  the  bones  of  cattle  and  birds  which  have  become  en¬ 
tangled  in  it,  lies  scattered  over  the  plain.  Before  1860,  the  experiment 
of  shipping  it  to  San  Francisco,  for  the  purpose  of  distilling  burning 
oil  from  it  had  been  tried,  without  success,  at  least  in  a  pecuniary  point 
of  view. 

The  plain  on  which  Los  Angeles  is  situated  is  celebrated  for  its 
beauty  and  fertility,  as  well  as  for  the  equable  character  of  its  climate. 
The  San  Gabriel  Range  to  the  north  of  it  furnishes  the  water  necessary 
for  its  irrigation,  from  the  melting  of  the  snow  which  accumulates  on 
its  highest  summits,  during  winters  in  which  the  precipitation  of  moist¬ 
ure  is  not  below  the  average.  The  ranches  along  the  base  of  the  moun¬ 
tains  are  especially  attractive,  and  the  vineyards  and  fruit  orchards 
have  already  become  quite  celebrated.  As  we  rise  towards  the  base  of 
Mount  San  Bernardino,  the  plain,  which  is  there  a  little  over  1000  feet 
above  the  sea,  becomes  dry,  and  in  places  is  covered  by  desert  sand. 
There  are  also  valuable  farming  lands  on  the  lower  portion  of  the  Santa 
Anna  River. 

Section  IV. — Santa  Anna  and  Temescal  Ranges. 

The  Santa  Anna  Range  is  an  exceedingly  broken  chain  of  moun¬ 
tains,  covered  almost  everywhere  with  the  thickest  chaparral  of  oaks 
and  ceanothus,  and  has  been  but  little  explored  or  traversed  even  by 
hunters.  It  begins,  on  the  northwest,  in  low  rolling  hills,  not  wooded, 


176 


GEOLOGY  OF  THE  COAST  RANGES 


which,  rise  near  the  San  Jos£  Creek,  and  it  extends  to  the  southwest  tor 
about  fifty  miles,  when  it  becomes  merged  in  the  broken  east  and  west 
ranges  which  traverse  the  country  to  the  north  of  the  Santa  Margarita 
River.  The  range  of  the  Santa  Anna  is  broken  through  by  the  river  ot 
the  same  name,  which  traverses  it  nearly  at  right-angles  to  the  direc¬ 
tion  of  the  chain.  At  the  point  where  it  intersects  the  range,  the  river 
has  an  elevation  of  437  feet  above  the  sea,  and  the  mountains  rise  to  an 
altitude  of  3033  feet  about  three  miles  south  of  it,  and  continue  to 
form  an  elevated  range  of  from  3000  to  5000  feet  as  far  south  as  we 
followed  it,  which  was  about  twenty  miles. 

Hear  the  Santa  Anna  River,  and  at  an  altitude  of  1500  feet  above  it, 
the  mass  of  the  mountain  was  found  to  be  made  up  of  coarse  sandstones 
and  conglomerates,  the  latter  containing  rounded  and  polished  pebbles 
of  granite,  jasper,  and  quartz.  The  whole  series  of  beds  dips  to  the 
northeast  at  a  high  angle,  being  in  many  places  nearly  vertical.  In  the 
sandstone  we  discovered  a  few  (cetacean?)  bones,  and  some  imperfect 
Tertiary  shells,  believed  to  be  of  Miocene  age.  The  strike  of  these 
beds  is  nearly  that  of  the  axis  of  the  chain,  or  about  northwest  and 
southeast;  the  dip  becomes  more  nearly  vertical  as  we  approach  the 
summit  of  the  mountain. 

An  immense  accumulation  of  detrital  material  lies  around  the  base 
of  the  range,  and  in  the  canon  of  the  Santa  Anna  River.  Just  below 
the  junction  of  this  stream  with  the  branch  coming  in  from  the  Temes- 
cal  Valley,  the  coarse,  unconsolidated  gravel  forms  great  tables,  350 
feet  in  height,  with  precipitous  sides  and  quite  bare  of  vegetation.  The 
same  kind  of  materials  occupies  the  bottom  of  the  Temescal  Valley, 
and  slopes  from  the  range  of  that  name  up  towards  the  Santa  Anna 
Mountains,  forming  an  accumulation,  at  their  base,  of  not  less  than  500 
feet  in  thickness,  furrowed  in  some  places  by  wide  canons  fully  200  feet 
deep.  These  gravels  are  the  “  wash”  of  the  mountains,  or  the  detritus 
brought  down  from  the  disintegrating  Tertiary  strata,  by  the  storms 
of  successive  winters.  Several  miles  farther  up  the  valley,  and  to  the 
west  of  the  Temescal  ranch-house,  the  same  sandstones  were  seen 
which  have  been  described  as  occurring  to  the  south  of  the  Santa  Anna 
River.  Here,  the  strike  is  H.  72°  W.,  and  the  dip  nearly  vertical. 
The  rock  is  almost  entirely  made  up  of  coarse  granitic  detritus. 


SOUTH  OF  LOS  ANGELES. 


177 


* 


The  culminating  point  of  the  Santa  Anna  Range  lies  about  seven 
miles  southwest  of  the  Temescal  ranch-house ;  it  can  he  best  ascended 
from  the  canon  of  Agua  Fria,  by  following  that  stream  up  for  about  a 
mile,  and  then  striking  off  to  the  south,  and  taking  one  of  the  main 
ridges  which  leads  to  the  summit.  The  highest  peak,  to  which  we 
gave  the  name  of  Mount  Downey,  in  honor  of  the  then  Governor  of 
the  State,  was  found  to  be  5675  feet  above  the  sea.  It  was  ascended 
January  26,  1861,  at  which  time  there  was  considerable  snow  scattered 
over  the  north  and  northeast  slope,  down  to  about  1000  feet  below  the 
summit. 

The  view  from  this  mountain  is  one  of  the  grandest  which  can  be 
had  in  the  Coast  Ranges.  The  range  of  vision  extends  along  the  coast 
from  Point  Duma,  near  the  end  of  the  Santa  Monica  Range,  to  the  Co¬ 
ronados  Islands,  a  distance  of  150  miles.  To  the  north  and  east  the  field 
of  view  is  bounded  by  the  vast  ranges  of  the  San  Gabriel,  San  Bernar¬ 
dino,  and  San  Jacinto,  all  capped  with  snow  during  the  winter,  and  fre¬ 
quently,  at  that  season,  tinged  with  the  deepest  rosy  hue  at  sunset. 
The  plain  to  the  northeast  of  the  Santa  Anna  River,  towards  San  Ber¬ 
nardino,  is  seen  to  rise  gradually  to  the  east,  and  to  be  traversed  by  a 
great  number  of  bare  granite  ridges,  generally  quite  isolated  from 
each  other,  deeply  furrowed  by  canons,  and  weathering,  on  the  sur¬ 
face,  into  immense  rounded,  boulder-like  masses.  Close  at  hand,  on 
the  east  and  northeast,  are  the  low,  gently  sloping,  and  almost  bare 
ridges  of  the  Temescal  Range,  the  highest  of  which  rises  to  about  half 
the  height  of  Mount  Downey.  On  the  south  is  what  may  wrell  be 
called  a  wilderness  of  mountain  ranges,  having  apparently  an  east  and 
west  trend,  and  closing  in  on  the  Ocean  north  of  the  Santa  Margarita 
River.  These  appear  to  be  from  3000  to  5000  feet  high,  very  rough, 
covered  with  chaparral,  and  consequently  very  little  known.  The  Santa 
Anna  Range,  itself,  is  seen  to  be  intersected  by  many  deep  canons, 
which  run  at  right-angles  to  the  general  direction  of  the  chain.  The 
most  southerly  point  seen,  on  the  main  land,  is  Table  Mountain  in 
Lower  California. 

This  portion  of  the  Santa  Anna  Range  is  chiefly  made  up  of  granitic, 
trappean,  and  metamorphic  rocks,  the  unaltered  sandstones  and  con¬ 
glomerates,  which  were  seen  on  the  point  ascended  near  the  Santa 


GEOL.  VOL.  T. — 23 


178 


GEOLOGY  OF  THE  COAST  RANGES 


Anna  River,  being  carried,  by  tlie  direction  ot  their  strike,  low  down 
on  the  slope  of  the  range,  in  its  southern  extension;  they  are  seen  at 
the  base  of  the  mountain,  and  appear  to  cross  the  valley  and  to  rise  on 
the  other  side  in  the  heights  of  the  Temescal  Range.  At  the  mouth  ot 
the  Agua  Fria  Canon,  granite  is  seen,  and,  next  above  it,  a  striped  jas- 
pery  rock,  which  is  a  metamorphic  slate,  such  as  has  often  been  seen 
among:  the  altered  Cretaceous  strata.  Above  this,  again,  is  another 
belt  of  granite,  passing  into  a  trappean  rock,  made  up  of  feldspar  and 
hornblende  in  tine  crystals,  the  hornblende  predominating,  so  as  to  give 
a  dark  color  to  the  mass ;  whether  this  was  an  eruptive  or  a  metamor¬ 
phic  rock  was  not  ascertained.  The  thickness  of  the  chaparral  on  the 
Santa  Anna  Range  would  render  the  exploration  of  it  extremely  diffi¬ 
cult.  Ro  indications  of  metalliferous  ores  were  observed  by  us  in  these 
mountains ;  but  it  will  be  a  long  time  before  they  are  thoroughly  ex¬ 
amined. 

The  Temescal  Rano-e  of  mountains  commences  on  the  south  side  of 

O 

the  Santa  Anna  River,  and  runs  southeast  in  a  direction  nearly  parallel 
with  that  of  the  chain  of  the  same  name,  from  which  it  is  separated  by 
a  narrow  valley.  The  northern  end  of  this  valley  is  drained  to  the 
northwest  by  the  Temescal  Creek,  a  tributary  of  the  Santa  Anna ;  in 
the  centre  there  is  a  lagoon,  which  is  the  sink  of  the  San  Jacinto  River, 
and  south  of  this  heads  the  Santa  Margarita.  The  whole  valley  is 
extremely  dry,  except  during  the  rainy  season,  and  the  adjacent  hills 
still  more  so,  too  dry  even  to  allow  of  the  growth  of  chaparral. 

The  Temescal  Range  approaches  closely,  in  its  southeastern  prolon¬ 
gation,  to  the  San  Jacinto  Mountains,  but  there  appears  to  be  a  wide 
and  low  pass  separating  the  two  ranges.  The  whole  region  to  the  south¬ 
east  and  around  San  Jacinto  is  entirely  unexplored,  so  far  as  we  can 
learn.  The  name  Temescal  seems  to  be  limited  in  its  application  to 
the  hills  lying  between  the  Santa  Anna  and  the  San  Jacinto  Creeks, 
and  which  cover  an  area  of  about  300  square  miles.  These  hills  are 
broken  and  irregular,  consisting  of  short  ridges  and  rounded  knobs, 
which  rise  from  a  few  hundred  to  a  thousand  feet  above  the  Temescal 
Valley,  which  at  the  ranch-house  was  found  to  be  776  feet  above  the 
sea.  Some  points  in  the  southern  part  of  the  range  are  probably  as 
much  as  2000  feet  above  tide. 


SOUTH  OF  LOS  ANGELES 


179 


On  the  southeast  side  of  the  range  the  rocks  exposed  are  chiefly  me- 
tamorphic  sandstone,  which  sometimes  occurs,  forming  large  masses 
of  nearly  pure  white  quartz-rock.  Near  the  Temescal  ranch-house  a 
stratified  semi-metam orpliic  sandstone,  passing  into  quartz,  was  seen, 
dipping  to  the  northeast,  at  an  angle  of  45°.  Farther  northeast,  the 
quartz-rock  is  succeeded  on  the  north  by  a  heavy  mass  of  porphyry ; 
this  rock  has  a  base  of  a  deep  slate-gray,  passing  into  dark-green  and 
chocolate-brown,  with  numerous  small  crystals  of  white  feldspar  scat¬ 
tered  through  it.  This  porphyry  is  a  material  of  great  beauty,  much 
resembling  some  of  the  fine  Swedish  varieties,  which  are  wrought  into 
vases  and  other  ornamental  articles.  Beyond  this  porphyry,  granite 
and  syenite  occur,  and  appear  to  make  up  the  whole  eastern  and  north¬ 
eastern  part  of  the  range.  This  rock  also  forms  numerous  low,  isolated 
ridges  and  knobs,  which  rise  in  the  desert  plain  lying  between  the  Te¬ 
mescal  and  San  Bernardino  Ranges.  Much  of  this  rock  has  a  concen¬ 
trically-laminated  structure  and  weathers  in  such  a  manner  as  to  give 
the  appearance  of  ridges  covered  with  drift-boulders,  as  seen  in  the 
annexed  wood-cut  (Fig.  29),  which  represents  one  of  these  weathered 


Fig.  29. 


GRANITE  RIDGE — NORTH  SIDE  TEMESCAL  RANGE. 


granitic  outcrops,  with  the  San  Bernardino  desert  beyond,  itself  covered 
with  similar  masses,  and  the  San  Gabriel  chain  in  the  distance. 


180 


GEOLOGY  OF  THE  COAST  RANGES 


A  canon  which  traverses  the  Temescal  Range  obliquely,  and  comes 
out  into  the  valley  about  three  miles  southeast  ot  the  ranch-house, 
shows  a  tine  section  of  the  rocks  of  the  southeastern  portion  of  these 
mountains.  The  sandstone  is  seen  here  in  all  stages  of  metamorphism, 
and  finally  passing  into  a  rock  almost  granitic  in  appearance.  It  is  not 
easy  to  say,  after  our  hasty  exploration  of  this  region,  what  is  the  age 
of  these  metamorphic  rocks ;  they  are  believed  to  be  partly  Cretaceous 
and  partly  Tertiary.  We  saw,  at  the  north  end  of  the  Santa  Anna 
Range,  heavy  masses  of  sandstone  strata,  between  one  and  two  thousand 
feet  in  thickness,  and  perhaps  more,  forming  the  flanks  of  these  moun¬ 
tains,  and  striking  across  the  valley  towards  the  Temescal.  It  would 
appear,  therefore,  that  the  quartzites  and  porphyries  of  the  last-named 
range  are  these  same  Tertiary  rocks  in  an  altered  condition.  It  would 
seem  probable  that  this  metamorpliism  was  connected  with  the  up¬ 
heaval  of  the  granite  on  the  northeast  side  of  the  range.  We  have 
already  noticed,  in  this  region,  along  the  Sierra  Santa  Monica,  the 
occurrence  of  extensive  uplifts  of  granite,  which  were  raised  after  the 
deposition  of  the  Miocene  Tertiary,  and  the  consequent  metamorphism 
which  extended  through  a  great  thickness  of  the  strata  of  this  age. 
The  geological  age  of  these  two  chains  would  appear  to  be  the  same, 
although  the  direction  of  the  lines  of  upheaval  is  different,  the  action 
of  the  upheaving  force  being  modified,  in  the  case  of  the  Temescal,  by 
the  proximity  of  the  vast  masses  of  the  San  Jacinto  and  San  Bernar¬ 
dino  Mountains.  We  must  expect,  in  this  part  of  the  State,  where  the 
geological  changes  of  various  ages  have  been  brought  to  a  focus,  as  it 
were,  that  the  resulting  phenomena  shall  be  found  extremely  complex 
and  difficult  to  decipher. 

The  Temescal  Range  was,  in  1860  and  1861,  the  scene  of  a  great 
excitement  on  the  subject  of  tin,  which  metal  was  supposed  to  occur 
here  in  large  quantity,  hundreds  of  claims  being  taken  up,  covering  all 
the  hills  and  ridges  for  miles  around.  Tin  ore  was  undoubtedly  found 
at  one  locality  in  these  hills  and  in  considerable  quantity,  as  specimens 
of  it  have  been  seen  in  various  collections  from  San  Francisco  to  New 
York.  The  ore,  which  appears  to  be  a  mixture  of  Cassiterite  (tin-stone 
or  oxide  of  tin),  with  more  or  less  earthy  and  mineral  matter,  resem¬ 
bling  a  mixture  of  the  hydrous  oxides  of  iron  and  manganese,  is  quite 


SOUTH  OF  LOS  ANGELES. 


181 


unlike  in  appearance  to  any  previously  seen,  and  its  true  character 
would  hardly  have  been  recognized  by  the  most  practised  mineralogist. 
Some  specimens,  assayed  in  New  York  and  Boston,  gave  as  much  as 
60  per  cent,  of  the  metal. 

The  locality  from  which  this  ore  was  obtained  was  the  so-called 
Cajalco  Mine,  about  three  miles  north  of  the  Temescal  ranch-house. 
Here  a  shaft  had  been  sunk,  in  the  winter  of  1860-61,  to  the  depth  of 
thirty-six  feet ;  but  it  was  partly  tilled  with  water  and  inaccessible  at 
the  time  of  our  visit.  A  great  number  of  the  “  claims”  taken  up  in 
this  vicinity  were  visited ;  they  seemed  nearly  all  to  be  located  on 
seams  or  streaks  of  dark  hornblende  running  irregularly  through  the 
granitic  and  highly  metamorpliic  rocks.  Although  there  was  no  ap¬ 
pearance  of  tin  about  any  of  these,  or  any  signs  of  regularity  in  the 
“  leads,”  a  great  many  specimens  were  collected  and  carefully  assayed 
for  tin,  without  there  being  a  trace  of  that  metal  found  in  any  one  of 
them.  The  excitement  has  undoubtedly  long  since  died  away,  and  it 
is  not  probable  that  the  mass  of  ore  in  the  Cajaleo  Mine  was  very  ex¬ 
tensive,  or  more  would  have  been  heard  of  it  before  this  time.  At  all 
events,  it  is  a  singular  and  interesting  occurrence  of  this  metal,  and  we 
know  of  no  other  locality  on  the  Pacific  coast,  north  of  Mexico,  where 
tin  ore  has  been  found  in  place.  A  single  fragment  of  this  substance 
was  given  us,  apparently  under  circumstances  justifying  credence  in 
the  discovery,  as  having  been  found  loose  in  the  soil  in  the  northern 
part  of  the  State,  near  Weaverville ;  but  the  vein  from  which  it  was 
derived  has  probably  never  been  discovered,  as  such  a  fact  could  have 
hardly  failed  to  become  widely  known. 

A  belt  of  limestone  crosses  through  the  Temescal  Valley,  as  was 
recognized  from  the  occurrence  of  numerous  fragments  of  this  rock 
on  the  surface ;  the  bed  itself  we  were  unable  to  discover.  It  is  of  a 
light-brown  color,  semi-crystalline  in  texture,  and  contains  minute 
organic  bodies,  of  which  the  exact  nature  could  not  be  made  out. 


182 


GEOLOGY  OF  THE  COAST  RANGES 


Section  V. — Islands  off  the  Coast  of  Southern  California. 

It  will  not  be  deemed  unsuitable  to  the  purposes  of  this  volume,  if 
we  give  such  information  in  regard  to  the  islands  off  the  California 
coast  as  we  have  obtained,  although  we  have  but  few  items  to  com¬ 
municate,  since  they  have  not  been  visited  by  any  of  the  geologists  of 
the  Survey.  Dr.  Cooper,  however,  spent  a  portion  of  the  spring  of 
1863  in  making  zoological  collections  among  these  islands,  and  has 
furnished  some  notes  on  their  geology  and  topography,  on  which  the 
most  of  what  here  follows  is  based. 

There  are  two  groups  of  islands  oft*  the  southern  coast  of  California. 
The  four  islands  Anacapa,  Santa  Cruz,  Santa  Rosa,  and  San  Miguel, 
with  the  rocks  seven  miles  west  by  north  from  the  latter,  form  one 
group,  and  these  all  lie  nearly  in  one  line,  and  have  their  longer  axis 
parallel  with  the  trend  of  the  shore  the  other  side  of  the  Santa  Bar¬ 
bara  Channel,  which  is  that  of  the  Santa  Inez  Range,  as  already 
noticed.  The  other  group  consists  of  San  Clemente,  Santa  Catalina, 
Santa  Barbara,  and  San  Nicolas,  with  John  Beggs’  rocks,  seven  miles 
from  San  Nicolas.  These  islands  all  have  a  trend  of  northwest  by  west, 
their  longer  axes  being  almost  exactly  parallel  with  each  other  and  with 
the  line  of  the  coast  of  the  main  land  opposite. 

Dr.  Cooper  encamped  on  the  island  of  Santa  Barbara  for  twenty 
days,  with  a  party  engaged  in  hunting  sea-lions.  He  describes  it  as 
composed  entirely  of  vesicular  basalt,  with  very  little  tendency  to  a 
columnar  structure,  and  nothing  like  a  volcanic  crater  or  lava  streams. 
There  is  an  imperfect  terraced  arrangement  due  to  the  action  of  water 
in  the  intervals  of  successive  upheavals,  of  which  three  or  four  seem 
to  have  occurred  since  the  island  was  raised  from  the  sea.  The  whole 
surface  is  covered  with  a  deep  and  apparently  good  soil,  containing  much 
lime,  very  light  and  ashy,  and  averaging  four  or  five  feet  deep  ;  it  seems 
difficult  to  account  for  its  uniformity  of  composition  and  depth,  except 
on  the  supposition  that  it  was,  to  a  great  degree,  formed  from  the  de¬ 
composition  of  animal  remains.  The  island  is  about  500  feet  high,  and 
has  two  miles  of  shore  line,  everywhere  rocky  and  abrupt*  and  present¬ 
ing,  on  the  northeast  and  south  sides,  perpendicular  cliffs  exposed  to  the 


SOUTH  OF  LOS  ANGELES. 


183 


full  force  of  the  ocean-swell.  The  area  of  the  summit  of  the  island  is 
about  thirty  acres,  and  near  fltb  highest  point  there  is  a  bed  of  shells 
of  living  species  and  very  fresh  appearance,  which  have  been  brought 
there  by  the  Indians,  who  formerly  resorted  to  this  place  for  eggs  and 
seals.  There  is  also  a  raised  beach,  about  thirty  feet  above  the  sea,  on 
the  southeastern  face  of  the  island,  in  which  are  found  shells,  one  spe¬ 
cies  of  which  has  not  been  discovered  elsewhere  on  the  coast  of  Cali¬ 
fornia.  This  bed  may  probably  be  of  the  same  age  as  the  Post-Plio¬ 
cene  strata  at  Santa  Barbara. 

In  regard  to  the  animal  life  of  this  island  Dr.  Cooper  remarks,  that 
it  is  now  the  resort  of  great  numbers  of  sea-lions,  and  was  also  for¬ 
merly  frequented  by  the  sea-elephant,  a  much  larger  species  of  seal, 
now  nearly  exterminated  along  this  coast.  Myriads  of  birds,  of  several 
species,  come  to  it  to  lay  their  eggs,  and  from  these  animals  the  large 
proportion  of  lime  in  the  soil  is  derived;  some  of  this  is  also  washed 
into  the  water,  thus  affording  the  necessary  calcareous  material  for 
the  shells  of  great  numbers  of  mollusca,  which  are  found  here  in  an 
abundance  quite  unusual  on  volcanic  islands.  The  land  is  perfectly 
alive  with  snails,  of  which  three  new  species  were  obtained,  one  of 
which  belonged  to  a  new  genus  (Binneya  notabilis).  These  land-shells 
appear  to  have  inhabited  the  island  from  a  very  early  period,  and  fossil 
forms  of  the  two  larger  species  are  found,  differing  considerably  from 
those  now  living. 

Santa  Catalina  is  seventeen  and  a  half  miles  long,  with  an  average 
breadth  of  four  miles  to  the  southern,  and  two  miles  to  the  northern 
portion,  the  island  being  divided  into  two  distinct  parts  by  a  transverse 
break  which  runs  through  it ;  the  divide,  at  this  break,  is  only  thirty 
feet  high,  while  the  hills  on  each  side  of  it  rise  to  an  elevation  of  from 
2000  to  3000  feet.  Dr.  Cooper  describes  the  rocks  as  being  chiefly 
metamorphic,  with  frequent  volcanic  outbursts  and  lava  streams  of 
vesicular  basalt.  Near  the  great  break  in  the  island  is  a  vein  of  ferru¬ 
ginous  matter,  about  a  foot  thick,  containing  masses  of  galena,  which 
may  be  traced  for  some  distance,  and  which  has  for  some  time  been 
known  to  exist  here.  On  this  vein  some  work  has  lately  been  done,  and 
the  galena  is  said  to  contain  silver.  There  is  one  good  spring  on  this 
island,  and  water  has  been  obtained  in  places  by  sinking  wells,  there 


184 


GEOLOGY  OF  THE  COAST  RANGES 


being  several  settlers  here,  engaged  in  raising  sheep.  Many  new  and 
interesting  species  of  shells  were  obtained  in  dredging  about  the  island, 
to  the  depth  of  120  fathoms. 

San  Nicolas  is  eight  miles  long  and  three  and  a  half  wide;  it  is  about 
600  feet  high,  and  the  summit  is  a  flat,  narrow  ridge,  from  which  the 
shores  on  both  sides  can  be  seen.  The  rock  is  exclusively  sandstone, 
apparently  of  a  late  geological  age,  but  containing  no  fossils,  so  far  as 
examined;  it  dips  to  the  east  at  an  angle  of  about  25°.  The  island  is 
distinctly  terraced  along  the  northeastern  side,  having  three  raised 
beaches  at  30,  80,  and  300  feet,  the  last  being  near  the  summit.  On 
these  terraces  are  shells  of  existing  species,  few  in  number  on  the  highest, 
but  more  numerous  on  each  succeeding  one  below,  and  most  of  all  on 
the  present  beach,  all  being  of  a  rather  northern  type.  The  summit 
appears  to  have  been  raised  from  very  deep  water  containing  no  shells; 
but  its  surface  is  now  strewn  with  shells  and  bones  left  there  by  the 
Indians.  This  island  is  occupied  as  a  sheep-ranch,  and  the  animals 
appear  to  thrive  remarkably  well,  although  the  vegetation  consists 
wholly  of  cacti,  and  other  plants  apparently  unfit  for  pasturage. 

San  Clemente  is  twenty-two  miles  long,  and  has  an  average  breadth 
of  two  miles.  It  consists  entirely  of  basalt,  which  has  a  somewhat 
columnar  structure,  especially  towards  the  southeast  end.  There  is 
scarcely  any  soil  covering  the  rock,  and  the  island  seems  never  to  have 
been  much  resorted  to  by  animals.  Its  form  is  that  of  a  terraced  table  ; 
and  although  from  the  nature  of  the  rock  and  the  scarcity  of  shells  but 
very  few  fossils  have  been  preserved,  yet  there  is  sufficient  evidence 
that  each  one  of  the  terraces,  of  which  there  are  about  seven,  has  been 
at  one  time  the  beach  of  the  island.  This  evidence  consists  of  the 
fact,  that  the  bluffs  forming  the  steps  from  one  terrace  to  another  are 
all  hollowed  out  by  numerous  caves,  like  those  existing  in  the  cliffs 
along  the  present  shore.  Some  of  the  latest  upheavals  have  greatly 
lengthened  the  island  at  the  northwest  end,  from  which  a  reef  now 
extends  out  about  a  mile,  while  along  the  middle  of  the  eastern  side,  a 
depth  of  600  feet  was  sounded  by  Dr.  Cooper  within  a  quarter  of  a 
mile  of  the  shore,  and  no  bottom  found  with  a  line  of  840  feet  at  a 
mile  distance.  The  elevation  of  the  highest  terrace  was  estimated  at 
1000  feet.  There  is  neither  wood  nor  water  on  this  island. 


SOUTH  OF  LOS  ANGELES. 


185 


It  will  be  noticed  that  the  interior  island  of  the  group,  Santa  Cata¬ 
lina,  presents  no  evidence  of  a  recent  elevation,  being  destitute  of  ter¬ 
races;  from  its  appearance  Dr.  Cooper  surmises  that  it  may,  on  the 
contrary,  be  sinking,  instead  of  rising.  The  vegetation  of  the  different 
islands  of  the  group  is  quite  dissimilar,  and  so  also  are  the  native  ani¬ 
mals, 'except  in  the  case  of  the  birds  and  quadrupeds  which  have  been 
carried  to  them  by  the  Indians,  or  borne  thither  on  floating  logs,  as  is 
the  case  sometimes.  It  is  a  curious  fact  that  sheep  thrive  on  Santa 
Barbara,  although  there  is  no  water  there  during  the  summer,  or  for 
more  than  half  the  year ;  they  appear  to  get  moisture  enough  from  the 
fogs  and  the  succulent  plants  on  which  they  feed.  Even  a  cat  has  suc¬ 
ceeded  in  sustaining  life  there  for  four  years,  living  on  birds  and  mice, 
of  which  there  is  an  abundance. 

Of  the  geology  of  the  more  northern  group,  consisting  of  Anaeapa, 
Santa  Cruz,  Santa  Ilosa,  and  San  Miguel,  but  little  is  known,  as  they 
were  not  visited  by  Dr.  Cooper,  with  the  exception  of  a  few  hours  spent 
near  Prisoner’s  Harbor,  on  Santa  Cruz.  In  the  “  Pacific  Coast  Direc¬ 
tory,”  drawn  up  by  Mr.  Davidson,  of  the  U.  S.  Coast  Survey,  and  pub¬ 
lished  in  the  Report  of  the  Superintendent  for  1862,  some  facts  are 
given  with  regard  to  these  islands.  Anaeapa,  which  is  in  reality  a 
group  of  three  islands  extending  in  a  nearly  E.  N.  E.  direction,  and 
five  miles  long,  is  made  up  of  coarse,  dark-gray  sandstone,  very  rotten 
and  crumbling,  with  perpendicular  sides  from  250  to  300  feet  high. 
The  soil  is  loose  and  thin,  producing  only  a  few  dwarfed  species  of 
cactus,  and  other  succulent  plants  common  to  the  sea-coast  in  dry,  sandy 
localities.  There  is  no  water  on  this  island.  Santa  Cruz  is  the  largest 
island  of  the  group,  being  twenty-one  miles  long  and  about  four  wide, 
and  1700  feet  high.  The  rock  is,  like  that  of  Anaeapa,  a  coarse,  crum¬ 
bling  sandstone,  somewhat  metamorphosed  in  the  vicinity  of  Prisoner’s 
Harbor.  Santa  Rosa,  fifteen  miles  long  and  ten  wide,  is  made  up  of 
rolling  hills,  covered  with  coarse  grass  and  bushes.  The  shores  are 
steep  and  broken,  and  destitute  of  a  harbor.  San  Miguel,  the  most 
western  of  this  group,  is  seven  and  a  half  miles  long  and  two  and  a 
half  broad.  These  two  last-mentioned  islands  are  probably  also  of 
sandstone,  judging  from  their  position  with  regard  to  the  others  of 
the  group.  Some  sheep  have  been  placed  on  San  Miguel ;  the  other 


GEOL.  VOL.  I. — 24 


186 


GEOLOGY  OF  THE  COAST  RANGES 


is  believed  to  be  entirely  worthless.  No  doubt,  interesting  zoologieal 
results  would  be  obtained  from  a  thorough  examination  of  this  group ; 
but  it  has  not  yet  been  in  our  power  to  have  it  done.  The  success  of 
mining  enterprises  on  any  of  these  islands  must  be  looked  upon  as  very 
doubtful. 


CHAPTER  VII. 

‘  THE  REGION  BETWEEN  THE  CANADA  DE  LAS  UVAS  AND 

SOLEDAD  PASS. 

A  rapid  reconnaissance  was  made,  by  Messrs.  Brewer  and  Gabb,  of  the 
region  between  the  T^jon  Pass  and  the  San  Emidio  Canon ;  and,  as  their 
observations  on  this  trip  were  chiefly  within  the  Coast  Ranges,  they  are 
given  in  this  connection,  although  they  include  also  a  little  of  the  terri¬ 
tory  which  properly  belongs  to  the  Sierra,  namely,  that  around  the 
Tdjon  Pass.  Indeed,  this  region  might  perhaps  be  called,  with  pro¬ 
priety,  the  debatable  ground  between  Sierra  and  Coast  Range.  How 
far  the  older  rocks  of  the  Sierra  may,  on  the  confines  of  the  Coast 
Range  upheavals,  have  participated  in  the  elevatory  movements  by 
which  this  last-named  system  has  been  raised,  and  whether,  in  some 
places,  rocks  older  than  the  Cretaceous  have  been  brought  to  the  surface 
in  the  centre  of  the  Coast  Ranges,  are  difficult  questions  to  answer  satis¬ 
factorily.  At  present,  we  have  no  evidence  that  any  other  than  the 
Tertiary  and  Cretaceous  formations,  and  the  associated  eruptive  masses, 
with  the  metamorphic  forms  of  these  two  groups  of  strata,  occur  in  the 
main  ranges  of  the  Coast  Mountains*  except  at  their  northern  and 
southern  extremities,  where  the  two  systems  are  brought  into  such  close 
contact  with  each  other. 

From  the  Kern  River  to  Canada  de  las  Uvas  is  about  thirty  miles, 
across  a  plain,  the  first  twenty  miles  of  which  is  a  low  alkaline  desert, 
in  some  places  bare,  in  others  covered  with  alkaline  shrubs.  At  about 
fourteen  miles  from  the  mouth  of  the  canon,  are  the  so-called  “  salt¬ 
works,”  where  the  soil  is  impregnated  with  salt  to  such  a  degree  that  a 
brine  sufficiently  pure  and  strong  to  preserve  meat  can  be  obtained  by 
lixiviation. 


BETWEEN  CANADA  DE  LAS  UVAS  AND  SOLEDAD  PASS.  187 


The  mountains  close  entirely  around  the  end  of  the  great  plain  of 
the  San  Joaquin  and  its  continuation  in  the  Tulare  Valley,  forming  a 
vast  amphitheatre,  unbroken  on  all  sides  except  to  the  north,  but  lowest 
to  the  west  at  Paso  Roble.  The  mountains  south  and  east  are  espe¬ 
cially  high,  rising  to  from  6500  to  8000  feet.  From  the  base  of  these, 
a  dry,  gravelly  or  sandy  slope  stretches  away  with  a  very  gentle  incli¬ 
nation  into  the  plain;  this  is  composed  of  coarser  materials,  and  has  a 
steeper  angle  near  the  mountains,  gradually  becoming  more  nearly 
horizontal  as  it  recedes  from  them.  This  detrital  deposit  covers  the 
base  of  the  mountains  to  the  height  of  a  thousand  feet  above  the- plain, 
and  is  made  up  of  the  materials  brought  down  the  slopes  of  the  moun¬ 
tains  by  the  wear  of  the  elements.  Near  the  mouth  of  the  canons  which 
issue  from  the  hills,  there  are  accumulations  of  boulders,  which  are  also 
scattered  over  the  plain  to  some  extent,  around  and  near  the  base  of 
the  hills. 

The  San  Emidio  Canon  lies  about  twenty  miles  west  of  the  Canada 
de  las  TJvas ;  it  has  its  origin  in  the  high  mountains  of  the  Coast 
Ranges,  at  Mount  Pinos  and  Mount  El  Dorado,  and  runs  nearly  north, 
opening  into  the  valley  of  Kern  and  Buenavista  Lakes.  It  owes  its 
form  to  the  agency  of  denuding  forces,  and  has  been  excavated  in  places 
to  a  depth  of  over  2000  feet.  Towards  the  head  of  this  canon,  granite, 
mica-slate,  syenite,  hornblende-slate,  and  limestone  are  found,  the  for¬ 
mation  having  a  general  strike  of  about  N.  75°  W. — S.  75°  E.,  and  a 
dip  to  the  south  of  from  70°  to  80°.  Resting  on  the  edge  of  these,  to 
the  north,  are  Cretaceous  strata,  overlain  in  their  turn  by  Tertiary  and 
Post-Tertiary  deposits,  chiefly  sandstones,  quite  unaltered  and  dipping 
to  the  north.  These  newer  rocks  form  a  belt  about  five  miles  wide  at 
the  mouth  of  the  canon,  extending  considerably  farther  into  the  plain 
at  that  point  than  they  do  on  either  side. 

The  Cretaceous  strata  are  of  inconsiderable  thickness  compared  with 
the  overlying  Tertiary.  They  consist  chiefly  of  sandstones ;  but  there 
are  also  intercalated  masses  of  shales,  with  nodular  concretions  of  argil¬ 
laceous  limestone,  such  as  are  common  in  this  formation  in  other  parts 
of  the  State.  But  few  fossils  were  found  in  the  Cretaceous  of  the  San 
Emidio  Canon ;  but  enough  were  collected  to  prove  conclusively  that 
the  strata  are  of  that  age.  The  beds  have  a  strike  of  N.  55°  W.,  and 
dip  north  at  an  angle  of  from  60°  to  70°. 


188 


GEOLOGY  OF  THE  COAST  RANGES 


These  Cretaceous  strata  are  succeeded  by  Tertiary  sandstones,  which 
overlie  them  conformably,  and  have  a  great  thickness.  The  lower 
members  of  the  Tertiary  are  quite  non-fossiliferous,  and  pass  gradually 
into  beds  which  are  undoubtedly  of  Miocene  age.  The  whole  series  is 
upturned  at  an  angle  of  60°  or  70°,  for  a  distance  of  about  two  miles, 
the  broken  strata  rising  into  sharp  ridges,  having  a  grandly  picturesque 
appearance.  Some  of  these  masses  of  rock  rise  to  the  height  of  nearly 
2000  feet  above  the  bottom  of  the  canon,  and  are  quite  bare  of  soil  and 
vegetation.  Some  portions  of  the  Miocene  strata  are  highly  fossilifer- 
ous,  but  the  fossils  are  very  poorly  preserved,  and  are  chiefly  in  the 
form  of  casts.  The  upper  members  of  the  Tertiary  consist  of  sand¬ 
stones  and  conglomerates,  the  latter  abundant  and  coarse,  and  appear¬ 
ing  to  be  more  recent  than  Miocene ;  they  are  probably  of  Pliocene 
and  Post-Pliocene  age.  All  these  are  disturbed  and  upturned,  to  the 
very  mouth  of  the  canon. 

Resting  unconformably  on  these,  for  three  miles  up  the  canon  from 
its  entrance,  are  beds  of  coarse  gravel,  forming  tables  several  miles 
wide,  which  are  cut  through  by  numerous  gorges,  beautifully  display¬ 
ing  their  structure.  These  detrital  beds  contain  immense  boulders  of 
granite,  of  the  same  character  as  that  found  in  the  mountains  to  the 
south ;  they  are  rounded  on  their  edges,  and  often  of  large  size,  some¬ 
times  as  much  as  six  or  eight  feet  in  diameter. 

The  annexed  section  (Fig.  30),  will  show  the  position  of  the  rocks  in 
the  San  Emidio  Canon.  It  extends  only  about  ten  miles  up  from  the 
plain,  and  not  as  far  as  the  summit  of  the  pass.  Farther  south,  the 
limestone  comes  in,  beyond  the  limits  of  the  section.  The  Miocene 
strata  (d)  rise  to  the  height  of  nearly  2500  feet  above  the  plain,  as  near 
as  could  be  estimated.  Their  dip  is  from  50°  to  65°. 

From  the  summit  of  the  higher  upturned  strata,  which  is  between 
2500  and  3000  feet  above  the  sea,  a  wide  belt  of  Tertiary  rocks  may  be 
seen  skirting  the  Coast  Ranges,  and  worn  into  rounded  hills,  which 
are  generally  barren,  especially  oil  the  west  side  of  the  Tulare  Valley. 
A  spur  runs  out  into  the  plain  to  the  west  and  northwest  of  Buena- 
vista  Lake,  and  widens  out  near  Paso  el  Roble,  extending  down  the 
valley  as  far  as  the  eye  can  reach.  Lying  south  of  the  cailon,  and 
about  its  head,  are  lofty  mountains,  of  which  Mount  Pinos,  the  domi- 


BETWEEN  CANADA  DE  LAS  UVAS  AND  SOLEDAD  PASS.  189 


nating  peak,  is  estimated  at  7500  to  8000 
feet  in  height. 

Passing  up  tlie  canon,  the  Cretaceous 
strata  are  seen,  resting  on  the  granite  and 
the  upturned  edges  of  the  mica  and  horn¬ 
blende  slates.  These  *  metamorphic  rocks 
are  dark-colored,  and  in  places  almost  black ; 
they  are  traversed  by  veins  of  light-colored 
granite,  having  the  mica  most  abundantly 
segregated  in  the  centre.  For  several  miles 
granite  alternates  with  gneiss,  mica-slate, 
and  silieious  metamorphic  rocks,  among 
which  some  beds  of  serpentine  occur.  This 
formation  dips  to  the  south  at  its  junction 
with  the  Cretaceous  rocks ;  farther  south  it 
is  vertical,  and  at  live  or  six  miles  from  the 
Cretaceous  it  inclines  to  the  north  at  a  high 
angle,  indicating  a  synclinal  structure  in  the 
range.  The  strike  of  the  metamorphic  beds 
is  about  15°  to  the  north  of  west.  Lime¬ 
stone  occurs,  in  a  highly  crystalline  condi¬ 
tion,  about  two  miles  north  of  Mount  Pinos, 
in  heavy  masses,  which  are  inclosed  in  mica- 
slate.  Magnetic  oxide  of  iron  is  also  found 
in  this  vicinity.  Sulphuret  of  antimony  oc¬ 
curs,  in  the  next  canon  west  of  the  San 

t 

Emidio,  namely  that  of  the  Arroyo  Plata, 
and  not  in  the  San  Emidio,  as  previously  re¬ 
ported. 

The  belt  of  Tertiary  extends  along  the 
flanks  of  the  mountains  eastward  for  about 
twenty  miles  from  the  San  Emidio  Canon, 
passing  out  into  the  plain,  and  terminating 
in  a  range  of  hills  to  the  northwest  of  the 
mouth  of  the  Canada  de  las  Uvas.  These 
hills  are  rounded,  and  deeply  furrowed  by  canons 


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190 


GEOLOGY  OF  TIIE  COAST  RANGES 


perhaps  800  feet  above  the  plain.  The  appearance  and  position  of 
these  beds  would  indicate  that  they  belong  to  a  very  late  Tertiary 
epoch,  although  fossils  were  not  discovered  in  them,  during  the  short 
stay  of  our  party  in  that  region.  The  rock  is  soft,  easily  disintegrated; 
and,  in  places,  the  sandstone  passes  into  a  white  shale. '  This  belt  of 
Tertiary  ceases  altogether  at  about  two  miles  west  of  the  entrance  of 
the  Canada  de  las  Uvas. 

The  canadas  called  “  las  Uvas”  and  “  los  Alisos”  are  narrow  valleys, 
through  which  flow  streams  or  “  arroyos”  of  the  same  names;  they 
both  head  in  the  granitic  and  metamorphic  rocks  of  the  mountain 
range  to  the  south,  opening  out  to  the  north  in  the  valley  of  Kern 
Lake,  and  cutting  through  a  narrow  belt  of  Cretaceous  rocks  as  they 
enter  the  plain,  being  in  fact  the  continuation  of  the  series  of  strata  of 
this  age  noticed  before  as  occurring  in  the  San  Emidio  Canon.  At  the 

Canada  de  las  Uvas,  the  Cretaceous  beds  form  a  belt  from  one-third  to 

* 

one-half  a  mile  wide,  mostly  covered  with  soil,  and  with  many  granite 
boulders,  derived  from  the  higher  mountains  north,  strewn  over  the 
surface.  The  exposures  are  but  few,  the  fossils  being  the  same  as 
th  ose  found  in  the  other  canons  east ;  in  the  one  next  to  the  Canada  de 
las  Uvas  the  Cretaceous  belt  is  somewhat  wider  than  it  is  in  another  one 
still  farther  in  the  same  easterly  direction ;  but  the  best  locality  for 
examining  the  strata  is  at  the  Canada  de  los  Alisos,  which  debouches 
into  the  plain  four  miles  east  of  the  Las  Uvas  Canon.  Here  the  Cre¬ 
taceous  belt  is  over  a  mile  wide,  the  strata  being  well  exposed,  although 
much  broken ;  they  form  hills  about  1000  feet  above  the  plain,  and 
2500  feet  above  the  sea,  the  general  level  of  the  base  of  the  range  be¬ 
tween  the  Canada  de  las  LTvas  and  the  Tejon  being  about  1500  feet 
above  the  tide-water. 

The  Cretaceous  strata  are  very  much  disturbed  in  this  region,  both 
dip  and  strike  being  quite  variable,  the  former  varying  from  N.  W.  and 
S.  E.  to  K.  E.  and  S.  W.,  while  the  dip  is  sometimes  to  the  north  and 
again  to  the  south,  and  generally  at  a  high  angle.  The  formation  con¬ 
sists  of  sandstones  and  conglomerates,  without  any  of  the  shales  so 
characteristic  of  the  Cretaceous  in  other  districts.  The  conglomerates 
are  very  coarse,  containing  many  boulders  from  three  to  six  inches  in 
diameter,  of  granite  and  metamorphic  rocks.  This  rock  resembles 


BETWEEN  CANADA  DE  LAS  UVAS  AND  SOLEDAD  PASS.  191 


very  closely  the  conglomerate  of  the  Upper  Cretaceous,  seen  near 
Pacheco’s  Pass.  Portions  of  the  sandstones  are  very  fossiliferous,  and 
the  shells  in  beautiful  preservation.  About  sixty  Cretaceous  species 
were  found  here  by  Messrs.  Brewer  and  Gabb  and  Hr.  Horn,  who  was 
stationed  for  some  time  at  Fort  Tejon,  and  collected  diligently  in  the 
vicinity.  It  was  from  this  formation  that  the  boulder  came,  which  was 
picked  up  at  the  mouth  of  the  Canada  de  las  Uvas,  and  which,  contain¬ 
ing  as  it  did  but  few  imperfect  fossils,  led  Mr.  Conrad  to  infer  the 
existence  of  the  Eocene  Tertiary  in  this  vicinity. 

Lying  outside  of  and  above  these  Cretaceous  strata,  along  the  margin 
of  the  plain,  are  beds  of  lava,  having  a  northern  dip.  This  formation 
begins  near  the  mouth  of  the  Canada  de  las  Uvas  and  extends  to  the 
east  and  southeast  for  a  considerable  distance.  At  Alisos  Creek,  these 
beds  are  not  over  200  or  300  feet  thick ;  but,  at  Arroyo  Pastoria,  they 
are  much  more  developed,  both  in  width  and  thickness,  and  continue 
to  increase  in  that  direction,  until,  at  Arroyo  Zapatero,  they  form  a 
wall  of  division,  as  it  were,  between  the  Sierra  Nevada  and  the  Coast 
Ranges.  The  rock  is  a  dark-colored,  hard  and  compact  basaltic  lava 
generally ;  but  some  portions  are  full  of  cavities,  and  weather  out  in 
small,  rounded  boulders,  which  cover  the  surface  of  the  adjacent  plain. 

The  Tdjon  reservation  and  plain,  on  which  is  the  Tdjon  ranch,  lies 
about  twenty  miles  northeast  of  Fort  Tejon  and  in  the  southeastern 
corner  of  the  Tulare  plain.  The  reservation  is  at  the  mouth  of  the 
Tejon  Canon,  where  the  plain  rises  in  a  gentle  slope  for  ten  miles,  and 
at  the  base  of  the  mountains  attains  an  elevation  of  1500  feet  above  the 
sea.  On  the  south  and  east  rise  high  mountains,  and  on  the  northeast 
there  stretches  along  the  base  of  the  Sierra  Nevada  a  line  of  low  hills, 
which  extend  out  into  the  plains  for  seven  or  eight  miles,  on  both  sides 
of  T£jon  Creek,  diminishing  in  width  as  they  stretch  to  the  northwest. 
These  hills  occasionally  attain  an  elevation  as  great  as  600  feet  above 
the  plain.  They  are  made  up  of  beds  of  coarse  sandstone  and  gravel, 
the  debris  of  granite  rocks,  with  occasional  boulders  of  compact,  gray 
lava.  They  lie  horizontally,  or  have  a  low  dip  to  the  west,  and  resem¬ 
ble  the  strata  at  Posd  Creek,  and  those  of  the  Tertiary  hills  north  of 
Kern  River,  of  which  a  description  will  be  given  farther  on.  To  the 
southwest  this  belt  of  Tertiary  elevations  stretches  towards,  but  does 


192 


GEOLOGY  OF  THE  COAST  RANGES 


not  connect  with,  the  range  of  hills  of  the  same  geological  age,  men¬ 
tioned  already  as  lying  to  the  northwest  of  the  Canada  de  las  Uvas. 
In  these,  however,  the  strata  are  disturbed  and  elevated,  and  therefore 
belong  to  the  Coast  Range  series,  while  the  Tertiary  beds  about  the 
Tejon  reservation  rest  in  their  original  position,  not  having  suffered 
any  derangement  since  their  deposition.  This  is  the  case  with  the 
Tertiary  and  Cretaceous  all  along  the  base  of  the  Sierra,  from  the  T£jon 
north,  as  will  be  seen  in  the  next  chapter. 

Everywhere  around  the  southern  end  of  the  Tulare  Valley,  and  on 
the  slope  that  rises  from  it  to  the  base  of  the  mountains,  the  soil  is 
better  than  it  is  on  the  lower  portions  of  the  plain,  supporting  a  luxuri¬ 
ant  growth  of  native  forage  plants.  Boulders  from  the  neighboring 
mountains  are  very  abundant  along  the  arroyos,  and  are  often  of  im¬ 
mense  size,  showing  the  magnitude  of  the  floods  by  which  they  have 
been  brought  down  from  high  up  in  the  canons.  In  the  San  Emidio 
Valley  a  mass  of  granite  was  seen,  which  was  estimated  to  contain  over 
1500  cubic  feet,  being  twenty  feet  long,  fifteen  wide,  and  projecting 
five  feet  out  of  the  soil  in  which  it  is  partially  embedded.  Vo  granite 
like  it  occurs  in  place  within  four  or  five  miles.  On  the  plain  outside 
of  the  San  Emidio  Canon  and  the  Arroyo  Plata,  are  many  boulders  of 
from  five  to  ten  feet  in  diameter;  and  they  are  equally  numerous, 
although  scarcely  as  large,  about  the  mouths  of  the  other  arroyos  com¬ 
ing  down  from  the  mountains  in  this  vicinity.  At  the  mouth  of  each 
canon  and  arroyo  the  detritus  forms  a  high  and  wide  embankment, 
which  extends  far  down  into  the  valley,  and  is  made  up  of  sand,  gravel, 
and  boulders.  The  water-courses  divide  over  these,  and  run  down  their 
sides  in  numerous  streamlets,  sinking  into  the  plain  and  disappearing 
a  few  miles  from  the  base  of  the  mountains. 

The  southeastern  end  of  the  Tulare  Valley  is  so  well  closed  in  by 
mountains,  that  there  is  no  low  pass  leading  out  of  it  into  the  Great 
Basin;  the  lowest  is  that  taken  by  following  up  the  north  fork  of  Tejon 
Creek,  through  a  narrow  canon,  at  present  without  a  trail,  and  crossing 
a  low  ridge  into  the  Taliichipi  Valley.  The  summit  on  this  route  is 
about  4000  feet  above  the  sea.  The  T£jon  Pass  proper  is  at  the  head 
of  T6jon  Creek,  and  is  given  in  the  Pacific  Railroad  Report  at  5285 
feet  above  the  sea;  this  route  is  now  but  little  used.  In  passing  up  the 


BETWEEN  CANADA  DE  LAS  UYAS  AND  SOLEDAD  PASS.  193 


Arroyo  del  Tejon,  near  the  entrance  of  the  canon,  mica-slate  is  seen, 
forming  a  belt  one  or  two  miles  wide,  having  a  strike  of  H.  30°  to  35° 
IV.,  and  a  high  dip  to  the  northeast.  This  rock  extends  off  to  the 
northwest  for  a  number  of  miles,  and  is  associated  with  limestone  to 
the  east  of  the  reservation.  This  limestone  was  not  seen  in  place,  but 
boulders  of  it  were  abundant  in  the  arroyo ;  it  is  white  and  has  a 
crystalline  texture. 

On  passing  the  belt  of  mica-slate,  granite  is  met  with,  which,  with 
gneiss  and  syenite,  forms  the  mass  of  the  mountains  between  the  T£jon 
and  Taliichipi  Valley.  The  higher  points  were  not  visited;  but  they 
appeared  to  be  of  massive  granite.  The  one  lying  to  the  south  of  the 
pass  is  given  in  the  Pacific  Railroad  Reports  at  6590  feet;  that  to  the 
north  was  estimated  at  6000  feet.  Granite  and  gneiss  constitute  the 
mass  of  the  chain  of  the  Sierra  in  the  region  of  Tahichipi  Pass. 

The  same  is  the  case  with  the  higher  portion  of  the  mountain  range 
extending  west  from  the  Tejon  Pass,  to  beyond  the  Canada  de  las  Uvas. 
In  this  latter  canon,  granite  and  gneiss  are  met  with,  after  crossing  the 
narrow  belt  of  Cretaceous,  before  noticed;  the  dip  of  the  gneissoid 
rocks  is  to  the  north  at  a  high  angle.  The  hills  are  very  steep  and  the 
canon  narrow;  but  on  reaching  Fort  Tejon  the  ravine  widens  out  into 
a  sort  of  valley,  which  extends  up  for  about  six  miles  and  then  branches 
off  to  the  east  and  west,  the  mountains  on  botli  sides  rising  to  the 
height  of  from  5500  to  6000  feet. 

Hear  Fort  Tejon  are  limestones,  running  H.  25°  to  35°  W.,  highly 
metamorpliic  and  containing  graphite.  This  mass  can  only  be  traced 
for  a  limited  distance.  The  western  branch  of  the  valley  above  the 
Fort  extends  for  twelve  miles  in  a  direction  about  15°  north  of  west, 
where  it  meets  a  similar  branch  of  the  San  Einidio  Canon.  On  the 
north  side  of  this  east  and  west  valley,  a  belt  of  limestone  extends  along 
the  whole  distance ;  it  crosses  the  San  Emidio,  and  was  followed  for 
several  miles  beyond,  without  coming  to  its  termination.  This  lime¬ 
stone  is  white  and  crystalline  and  contains  graphite,  distributed  in 
layers,  so  as  to  give  the  rock  a  stratified  appearance,  as  was  noticed  in 
the  limestone  of  the  Gavilan  Range.  The  thickness  of  the  belt  is  esti- 
mated  at  200  feet,  but  it  is  not  uniform ;  its  dip  is  at  a  high  angle  to 
the  north.  Associated  with  it  are  mica-slates  and  some  gneiss,  toge- 


GEOL.  VOL.  T. — 25 


€> 


194 


GEOLOGY  OF  THE  COAST  RANGES 


ther  with  masses  of  magnetic  iron  ore.  In  the  valley  the  boulders  are 
of  every  variety  of  granitic  and  metamorphic  rocks,  especially  of  mica 
and  hornblende-slates  and  quartz ;  the  predominating  rock  is  gneiss, 
with  a  very  much  contorted  lamination.  Some  of  the  granite  contains 
very  large  crystals  of  rose-colored  feldspar.  This  same  line  of  depres¬ 
sion  is  carried  across  the  head  of  the  San  Emidio  Canon,  which  there 
separates  into  two  valleys  east  and  west.  South  of  these  are  the  highest 
points  of  the  chain,  that  to  the  south  of  the  east  branch  being  known 
as  Mount  Pinos,  estimated  at  over  7000  feet,  and  that  south  of  the  west 
fork  is  the  mountain  called  El  Dorado,  which  is  nearly  as  high  as 
Mount  Pinos.  The  north  slopes  of  these  are  of  gneiss  and  mica-slate ; 
the  summits  are  said  to  be  of  granite,  but  for  want  of  time  they  were 
not  ascended  by  our  party. 

In  passing  down  the  San  Emidio  Canon,  from  the  forks,  after  cross¬ 
ing  the  limestone,  various  forms  of  metamorphic  rock  were  observed, 
such  as  mica  and  hornblende-slates  and  gneiss,  traversed  by  large  veins 
of  granite.  There  was  also  some  serpentine  and  silicious  metamorphic 
rock.  This  region  has  been  frequently  prospected  for  silver,  although 
no  indications  of  valuable  veins  were  seen.  It  is  said  that  over  $50,000 
has  been  expended  here. 

In  passing  southeast  from  the  summit  of  the  pass  of  the  Canada  de 
las  Uvas,  we  follow  down  a  valley  for  several  miles,  having  on  its 
northern  side,  a  belt  of  limestone  which  is  often  highly  crystalline  and 
contains  graphite ;  in  places  it  is  accompanied  by  a  belt  of  a  ferruginous 
metamorphic  rock,  containing  magnetic  oxide  of  iron,  and  a  similar 
rock  was  seen  associated  with  the  limestone  of  the  San  Emidio  Canon. 

Four  miles  east  of  the  summit  of  the  Canada  de  las  Uvas  Pass,  are 
two  small  salt  lakes,  dry  during  a  portion  of  the  year,  called  on  the 
Pacific  Railroad  maps  the  Casteca  Lakes.  Here  Tertiary  rocks  are  met 
with,  having  a  strike  of  about  U.  60°  E.,  and  a  high  dip  to  the  north¬ 
west.  These  strata  form  a  wide  belt  which  extends  off  to  the  south¬ 
west,  apparently  passing  through  a  low  gap  between  the  high  granite 
mountains  which  lie  south  of  the  Canada  de  las  Uvas,  and  other  high 
(granite  ?)  ranges  to  the  southeast.  It  is  said,  that  a  low  divide  extends 
through  to  the  headwaters  of  the  Cuyamas  River,  and  this  Tertiary 


BETWEEN  CANADA  DE  LAS  UVAS  AND  SOLEDAD  PASS.  195 


apparently  passes  through  it  and  connects  with  the  great  masses  of  the 
same  formation  along  the  coast. 

This  Tertiary  extends  southeast  and  east  for  several  miles,  then  passes 
under  the  more  modern  detritus  of  the  desert  and  disappears.  Near 
the  Liebre  ranch-house,  the  strata  are  much  broken,  and  were  noticed 
to  run  in  various  directions*  from  N.  35°  E.  to  N.  60°  E.,  and  to  dip 
sometimes  to  the  north  and  sometimes  to  the  south,  and  occasionally  to 
stand  vertically.  No  fossils  were  detected  in  these  rocks,  but  they  are 
believed  to  be  undoubtedly  of  Tertiary  age,  from  their  connection  with 
other  rocks  of  this  age  in  the  Great  Basin.  These  rocks  skirt  the 
desert  on  the  south  side  to  about  two  miles  east  of  the  Liebre  ranch- 
house,  where  they  pass  under  the  plain.  Here  a  belt  of  volcanic  mate¬ 
rials  makes  its  appearance,  lying  immediately  south  of  the  Tertiary. 
This  rock  is  generally  very  hard,  and  portions  of  it  have  a  bedded  or 
stratified  appearance ;  where  it  has  an  amygdaloidal  structure,  the 
cavities  are  filled  with  chalcedony.  At  the  ranch-house  it  forms  a  belt 
at  least  two  miles  wide,  and  extends  east,  forming  the  margin  of  the 
plain,  for  eight  or  ten  miles.  South  of  this,  is  a  high  granite  ridge, 
covered  with  chaparral,  which  extends  east  and  comes  out  to  the  plain 
about  ten  or  twelve  miles  northeast  of  Lake  Elizabeth,  forming  the 
marginal  hills  up  to  the  point  where  the  road  over  the  San  Francisquito 
Pass  crosses,  which  is  as  far  as  was  explored  by  our  party  in  this  direc¬ 
tion. 

To  the  north  of  this  granite  ridge  is  a  vast  mass  of  unexplored  moun¬ 
tains,  bounded  on  the  south  by  the  Santa  Clara  Valley,  and  forming 
the  nucleus,  so  to  speak,  from  which  start  out  to  the  west  the  different 
ranges  of  the  Coast  Mountains.  There  are  two  passes  across  these 
mountains,  leading  down  into  the  Santa  Clara  Valley  and  thence  by 
the  San  Fernando  Valley  to  Los  Angeles.  Of  these  the  Soledad,  as  it 
is  now  called,  was  discovered  by  Lieutenant  Williamson,  and  named 
by  him  “  New  Pass.”  This  pass  runs  nearly  east  and  west,  and  rises 
to  the  height  of  3164  feet  at  its  summit.  A  few  miles  to  the  northwest 
of  the  head  of  the  pass  is  StonemaiTs  Mountain,  6000  feet  high,  as 
given  by  Williamson.  The  San  Francisquito  Pass  follows  up  the  branch 
of  the  Santa  Clara  of  the  same  name,  and  comes  out  to  the  northeast 
at  Lake  Elizabeth,  having  an  elevation  of  3718  feet  at  its  summit.  This 


196 


GEOLOGY  OF  TIIE  COAST  RANGES 


pass  was  once  of  considerable  importance,  being  on  the  route  of  the 
Overland  Mail  from  Los  Angeles  to  San  Francisco;  but,  of  later  years, 
the  coast  road  lias  been  followed,  by  Santa  Barbara  and  down  the  Sa¬ 
linas  Valley.  The  Soledad  Pass  has  been  better  known,  of  late,  from 
various  attempts  made  to  work  copper  mines  there,  large  numbers  of 
samples  of  cupriferous  ores,  especially  of  the  green  carbonate,  having 
been  brought  from  this  region  in  1862-3.  It  is  not  known  that  any 
permanent  veins  have  been  discovered,  and  worked  with  profit.  A 
belt  of  metamorphic  rocks  stretches  through  here,  and  crosses  the  San 
Francisquito,  where  placer  gold  mining  is  carried  on  at  intervals  to  some 
extent.*  This  belt  of  metamorphic  is  referred  by  us  to  the  Cretaceous 
formation ,-  from  general  analogy,  rather  than  from  any  direct  evidence  of 
fossils,  But  little  is  known  either  of  the  topography  or  geology  of  the 
rough  and  mountainous  country  lying  to  the  west  of  the  San  Francis¬ 
quito  Canon. 

In  crossing  the  desert,  from  the  Liebre  ranch-house  to  the  mountains 
eight  or  ten  miles  northwest,  between  the  Tejon  Pass  and  the  Canada 
de  las  Uvas,  the  desert  plain  is  observed  to  rise  with  a  steeper  slope 
against  the  mountains  on  the  north  than  it  did  on  the  other  side  of  the 
desert.  At  the  southern  base  of  the  range,  between  the  two  passes 
above-mentioned,  there  is  a  narrow  belt  of  marginal  hills,  covered 
with  thick  soil,  but  underlain  by  white  slates  or  shales,  supposed  to  be 
of  Tertiary  age,  and  resembling  closely  the  bituminous  shales  of  the 
Coast  Ranges.  North  of  this  is  soft  granite,  which  rises  into  moun¬ 
tains  over  5000  feet  high.  This  is  much  cut  up  into  canons,  and  fur¬ 
nishes  the  granitic  sand  so  abundant  in  the  desert.  Limestone  is  said 
to  occur  farther  northeast,  near  where  the  old  Fremont  trail  issues  on 
to  the  desert,  In  the  centre  of  the  chain,  which  is  here  about  eleven 
miles  wide,  there  are  said  to  be  pleasant  valleys  with  fine  timber  and 


*  It  was  somewhere  in  this  vicinity  that  gold  was  first  obtained  in  California  in  con¬ 
siderable  quantity  and  from  regular  washings.  This  was  as  early  as  1841.  M.  Duflot  de 
Mofras  says  that  the  locality  was  in  the  mountains  six  leagues  north  of  the  San  Fernando 
Mission,  and  fifteen  leagues  from  Los  Angeles,  where  the  dust  was  brought  for  sale. 
Major  J.  Bidwell,  of  Chico,  has  also  given  us  some  particulars  as  to  these  early  gold-wash¬ 
ings,  with  the  details  jof  which  he  was  well  acquainted.  Work  was  kept  up  for  several 
years. 


BETWEEN  CANADA  DE  LAS  UVAS  AND  SOLEDAD  PASS.  197 


pasturage,  and  abundance  of  water.  All  the  land  of  any  value  along 
the  foot-hills  is  covered  by  Spanish  (?)  grants. 

The  plains  on  either  side  of  these  mountains  are  destitute  of  trees, 
but  support  more  or  less  shrubby  vegetation  and  a  limited  amount  of 
forage.  The  mountains  have  considerable  timber;  the  drier  ridges  are 
covered  with  chaparral  and  stinted  trees  of  the  species  Pinus  Fremonti- 
ana  (the  one-leaved  pine).  Where  there  is  more  moisture,  there  is  a 
larger  and  more  abundant  growth  of  timber,  especially  of  Pinus  ponde- 
rosa  and  P.  Jeffreyi ,  the  latter  especially  fine.  In  the  valleys  there  are 
numerous  oaks,  among  which  are  Quercus  lobata  (syn.  Hindsii)  and  Q. 
crassipocula ,  but  neither  of  these  is  fit  for  timber.  These  are  the  prin¬ 
cipal  varieties  of  forest  trees  ;  there  are  several  other  species,  but  not 
in  sufficient  abundance  to  be  of  importance,  nor  is  their  timber  of 
value.  The  great  distance  of  this  region  from  a  market,  and  from  any 
considerable  mines,  renders  it  of  much  less  importance  than  it  would 
otherwise  be.  There  are  no  gold  washings  or  quartz  veins  or  any  other 
metalliferous  deposits  known,  which  can  be  made  available  under  the 
present  conditions,  any  nearer  than  Kern  River. 


» 

■ 


I 


H?  _A_  E;  T  II. 


THE  GEOLOGY  OF  THE  SIERRA  NEVADA. 


CHAPTER  VIII. 

THE  UNDISTURBED  MARINE  SEDIMENTARY  ROCKS  ALONG  THE 

FOOT-HILLS  OF  THE  SIERRA. 

Following  the  method  of  arrangement  which  seems,  on  the  whole, 
best  adapted  to  the  circumstances,  we  proceed  next  to  take  up  the  Geol¬ 
ogy  of  the  Sierra  Nevada ;  and,  as  we  have  in  the  preceding  pages  suffi¬ 
ciently  explained  what  the  criterion  is  by  which  we  separate  the  Coast 
Ranges  from  the  Sierra,  there  is  no  occasion  to  dwell  farther  on  it  in 
this  place,  as  it  is  a  subject  which  will  come  up  for  discussion  at  a 
future  time  and  place.  We  need  only  specify  here  what  will  he  the 
order  of  arrangement  in  this  Part  of  the  present  volume. 

Our  observations  have  shown  us  that  there  is,  along  the  base  of  the 
Sierra,  a  belt  of  unaltered  strata  of  marine  origin,  which  belongs  to  the 
Tertiary  and  Cretaceous  systems;  this  belt  may  be  traced  from  Fort 
Tejon  to  Fort  Reading,  no  longer  forming  one  connected  whole,  hut 
occurring  in  patches,  some  of  which,  however,  occupy  quite  an  exten¬ 
sive  area,  especially  those  near  the  heads  of  the  Sacramento  and  San 
Joaquin  Valleys.  Denudation  has  swept  off  the  greater  portion  of  this 
formation  through  the  central  part  of  the  State,  a  few  limited  outliers 
being  all  that  remains  along  the  foot-hills  between  the  Stanislaus  and 
the  Yuba.  These  undisturbed  sedimentary  rocks,  to  which  the  present 
chapter  will  be  devoted,  are  of  marine  origin,  being  in  many  places 
abundantly  supplied  with  fossils  which  afford  ample  evidence  of  their 
geological  age,  as  well  as  of  the  nature  of  the  medium  in  which  they 
were  deposited.  These  marine  strata  do  not  rise  to  a  great  height  on 


200 


GEOLOGY  OF  THE  SIERRA  NEVADA 


the  flanks  of  the  mountains,  and  are  not  at  all  to  he  confounded  with 
the  vast  sedimentary  accumulations  of  fresh-water  origin,  which  cover 
so  considerable  a  portion  of  the  Sierra,  and  extend  to  so  great  altitude 
above  the  sea-level. 

This  latter  formation,  as  being  chiefly  developed  in  the  mining  region 
of  the  Sierra,  and  of  great  importance  for  the  auriferous  deposits  which 
it  contains  or  covers,  will  be  taken  up  in  the  second  Chapter  of  this 
Part  of  the  volume  (Chapter  IX),  which  will  he  devoted  to  the  gold¬ 
mining  region  proper  of  the  State,  or  the  western  slope  of  the  Sierra, 
especially  the  lower  portion  of  it,  which  was,  until  within  the  last  three 
or  four  years,  essentially  the  only  mining  district  of  the  Pacific  States; 
it  is  now  obliged  to  divide-  the  honors  with  other  regions  north,  south, 
and  east. 

In  Chapter  X  of  this  Part,  we  will  give  such  information  as  our 
limits  and  means  permit,  with  regard  to  the  Higher  Sierra,  or  the  more 
elevated  portions  of  this  range,  beyond  the  region  of  mining  settle¬ 
ments,  or,  at  least,  of  such  as  may  be  considered  to  be  permanently 
established  and  pecuniarily  successful. 

After  this  will  follow,  in  Chapter  XI,  a  notice  of  the  valleys  and 
ranges  beyond  the  summit  of  the  Sierra,  or  along  the  “Eastern  Slope,” 
as  it  is  usually  called;  to  this  will  be  appended  what  little  we  have  to 
say  in  regard  to  the  “  Great  Basin,”  or  “  Great  Desert”  as  it  is  fre¬ 
quently  called,  meaning  that  portion  of  the  State  which  lies  to  the 
south  and  east  of  the  Sierra,  towards  the  Colorado  Biver,  and  which  is 
covered  by  a  succession  of  almost  unknown  mountain  ranges,  with 
barren  and  inhospitable  plains  between  them. 

Thus,  these  two  Parts  will  be  found  to  have  included  the  principal 
geological  facts  developed  during  what  may  be  called  a  reconnaissance 
of  the  State  of  California.  The  task  of  arranging  and  co-ordinating 
these  facts,  so  as  to  draw  from  them  the  important  general  conclusions 
for  which  they  furnish  the  material,  will  still  remain  to  be  accom¬ 
plished.  Whether  this  work  will  be  entered  upon  at  once,  as  a  con¬ 
tinuation  of  this  volume,  or  whether  it  will  be  postponed  until  a  farther 
store  of  facts  shall  have  been  added  to  those  already  gleaned  from  this 
wide  field,  will  depend  on  the  action  of  the  next  Legislature,  as  will  be 
found  fully  set  forth  in  the  introductory  chapter  to  this  Report. 


ALONG  THE  FOOT-HILLS. 


201 


The  base  of  the  foot-hills  of  the  Sierra  Nevada  is  bordered,  for  a  large 
part  of  the  distance  between  T6jon  Pass  and  the  head  of  the  Sacramento 
Valley,  by  a  series  of  beds  of  stratified  materials,  resting  apparently 
undisturbed,  and  in  a  nearly  horizontal  position,  on  the  upturned  edges 
of  the  metamorphic  slates  and  granitic  rocks  of  which  the  foot-hills  are 
formed.  These  unaltered  strata  are  all  marine  deposits,  and  are,  in 
places,  well  supplied  with  the  remains  of  marine  shells  and  other  fossils. 
They  are  not  to  be  confounded  with  the  stratified  masses  which  occur 
on  the  flanks  of  the  Sierra,  but,  for  the  most  part,  higher  up  in  the 
mountains,  and  which  are  also  of  detrital  origin.  These  contain,  how¬ 
ever,  only  the  remains  of  fresh-water  or  land  animals  and  plants,  and 
are  of  great  importance  for  the  gold  they  contain ;  the  marine  beds,  on 
the  other  hand,  have  no  such  significance,  and  are  nowhere  worked  for 
the  precious  metal. 

This  belt  of  marine  sediments,  in  the  northern  part  of  the  State,  is 
chiefly  Cretaceous ;  but  no  rocks  of  this  age  are  seen  farther  south  than 
Folsom,  so  far  as  known;  beyond  this,  to  the  Tejon  Pass,  they  all 
belong  to  the  Tertiary  age. 

Commencing  at  the  southern  extremity  of  the  Tulare  Valley  with 
our  notice  of  these  rocks,  we  find  the  greatest  development  of  the 
Tertiary  beds  between  Kern  and  White  Rivers.  This  belt  begins  on 
the  north,  three  miles  beyond  White  River,  and  it  here  forms  low  hills 
of  very  soft  sandstone,  lying  horizontal,  or  having  a  low  dip  away  from 
the  mountains.  In  many  places,  the  denudation  of  this  soft  material 
shows  the  original  flooring  of  granite  on  which  the  Tertiary  was 
deposited. 

From  White  River  to  Kern  River,  about  30  miles,  the  Tertiary  sand¬ 
stones  occur  all  the  way,  forming  rounded  hills  from  200  to  600  feet 
high,  the  rock  being  soft  and  chiefly  made  up  of  granitic  detritus, 
evidently  derived  from  the  mountains  to  the  east,  and  having  a  low  dip 
to  the  west,  generally  less  than  six  degrees,  and  often  horizontal ;  there 
is  no  reason  to  suppose  that  these  beds  have  been  disturbed  since  their 
deposition.  The  fossils  obtained  in  these  strata  were  referred  by  Mr. 
Gabb  to  the  age  of  the  Miocene  Tertiary.  The  upper  portions  of  some 
of  the  hills  are,  however,  of  a  later  formation,  and  of  fresh-water  origin, 
as  they  contain  fragments  of  bones  and  wood. 


GEOL.  VOL.  T. — 26 


202 


GEOLOGY  OF  THE  SIERRA  NEVADA 


From  Kern  River  to  King’s  River,  the  metamorphic  and  granitic 
rocks  continue  into  the  valley,  until  covered  by  the  recent  detritus;  hut 
north  of  King’s  River,  as  far  as  the  Stanislaus,  there  is  a  belt  of  low 
flat-topped  and  dome-shaped  hills  of  sandstone,  rising  100  to  150  feet 
above  the  level  of  the  plain.  A  little  north  of  the  Merced  River,  to  the 
west  of  the  road  from  Bear  Valley  to  Stockton,  a  very  handsome 
variety  of  sandstone  was  observed,  forming  low  cliffs  near  the  summit 
of  a  hill  about  150  feet  high.  This  rock  was  a  fine-grained  free-stone, 
elegantly  ornamented  with  fine,  waving,  and  concentric  lines  and  hands 
of  a  light  rose-red  color.  For  some  kinds  of  architectural  purposes, 
this  stone  would  be  a  very  desirable  material. 

There  is  little  variety  in  these  Tertiary  hills,  for  a  long  distance ;  they 
are  scattered  over  the  plain  of  the  San  Joaquin,  at  the  base  of  the  foot¬ 
hills,  the  deposit  never  having  been  very  thick,  and  having  been  very 

v 

irregularly  denuded,  so  as  to  leave  many  small  patches,  which  could 
only  be  laid  down  on  the  map  after  a  minutely-detailed  survey. 

The  first  exposure  of  rocks  of  Cretaceous  age  along  the  base  of  the 
Sierra,  in  proceeding  •north,  so  far  as  we  have  observed,  is  at  Folsom. 
Here,  on  the  north  side  of  the  American  River,  a  little  below  the  rail¬ 
road  bridge,  is  an  inconspicuous  exposure  of  sandstones,  with  a  mod¬ 
erate  dip  down  the  valley,  in  which  a  considerable  number  of  speci¬ 
mens  of  Exogyra  'parasitica  were  found ;  a  single  Ammonite  ( A .  com- 
plexus? ),  in  the  collection  of  the  California  Academy  of  Natural  Sciences, 
was  also  obtained  at  this  place.  There  are  other  localities  of  Cretaceous 
fossils  in  this  vicinity ;  hut  we  have  not  yet  found  time  to  search  them 
out.  Ho  doubt  there  are  many  scattered  patches  of  strata  of  this  age, 
which  have  escaped  observation,  along  the  foot-hills  from  here  towards 
the  north. 

One  of  these  occurs  between  Beal’s  Bar  and  the  Halfway  House, 
near  the  line  of  Sacramento  and  Placer  Counties,  and  not  far  from 
Texas  Flat.  This  locality  was  discovered  by  Dr.  Trask,  and  a  large 
number  of  species  of  Cretaceous  fossils  collected  there  by  him,  and 
deposited  in  the  collection  of  the  California  Academy  of  Natural  Sci¬ 
ences,  and  thus  rendered  accessible  for  scientific  description.  The 
grouping  of  the  species  at  this  locality  is  peculiar,  quite  a  number  being 
found  there  which  have  not  been  discovered  elsewhere  in  the  State. 


ALONG  THE  FOOT-HILLS. 


203 


The  following  is  a  list  of  them,  as  recognized  or  described  by  Mr.  Gabb, 
the  species  peculiar  to  this  locality  being  indicated  by  an  asterisk : 


Gyrodes  expansa, 

ClNULIA  OBLIQUA, 

*Discohelix  Leana, 
*Straparollus  paucivolvus, 
*S.  LENS, 

Angaria  ornatissima, 
Aporrhais  falciformis, 
*Littorina  compacta, 

*Lysis  duplicosta, 

*EmARGINULA  RADIATAj 
*Patella  Traskii, 

*IIelcion  dichotoma, 
Cylichna  costata, 
Martesia  clausa, 

CORBULA  TrASKII) 


Mactra  Ashburnerii, 
*Asaphis  undulata, 
*Tellina  monilifera, 
*Trapezium  carinatum 
*Cardium  Placerensis, 
*Lucina  postradiata, 
*L.  SUBCIRCULARIS, 
Loripes  dubia, 
*Astarte  Conradiana, 

CUCULL^A  TRUNCATA, 

Axin^ea  Yeatchii, 
*Pecten  Traskii, 
*Anomia  lineata, 
Exogyra  parasitica, 
*Terebratella  obesa. 


According  to  Dr.  Trask’s  notes*  which  he  has  kindly  placed  at  our 
disposal,  it  appears  that  the  fossiliferous  bed  was  struck  at  a  depth  of 
forty  feet  below  the  surface,  in  a  mining  shaft ;  the  following  is  a  sec¬ 
tion  of  the  strata  passed  through  in  sinking  at  this  place,  enumerated 
in  a  descending  order : 


Gravelly  detritus  and  granitic  sand, 

cemented  by  oxide  of  iron, 

40  feet. 

Sandstone,  .... 

•  •  •  • 

14  inches. 

Argillaceous  sandstone,  with  fossils, 

•  •  *  • 

2  feet. 

Blue  clay,  with  sharks’  teeth, 

•  *  •  • 

8  inches. 

Fossiliferous  sandstone, 

•  •  •  • 

1  foot. 

Blue  clay  and  sharks’  teeth, 

k  k 

8  inches. 

Brown  sandstone,  .  .  . 

•  •  k  • 

25  feet. 

It  appears  that  there  are  several  localities  in  this  vicinity  where  the 
same  fossiliferous  bed  might  be  found,  as  Dr.  Trask  remarks  that  it 
occurs  near  Texas  Flat,  Halfway  House,  Volcano  Ridge,  and  Mississippi 
Flat,  and  he  estimates  its  elevation  at  from  800  to  1000  feet  above 
the  sea. 

Quite  an  extensive  belt  of  Cretaceous  rocks  occurs  in  the  northern 
part  of  the  Sacramento  Valley,  along  the  slope  of  the  Sierra  Nevada, 
between  Feather  and  Pit  Rivers,  although  a  large  portion  of  the  forma- 


204 


GEOLOGY  OF  THE  SIERRA  NEVADA 


tion  is  covered  by  an  overflgw  of  volcanic  materials,  so  that  the  under¬ 
lying  sedimentary  rocks  can  only  be  seen  where  these  have  been  deeply 
denuded.  The  best  exposures  of  the  Cretaceous  commence  a  little  to 
the  north  of  Oroville,  and  they  may  be  seen  to  advantage  on  Butte 
and  Chico  Creeks.  A  small  area  is  exposed  by  the  erosion  of  the  lava, 
near  Antelope  Creek,  but  from  beyond  that  as  far  as  Cow  Creek,  near 
Fort  Beading,  the  lava  comes  entirely  down  to  the  plain,  quite  covering 
the  Cretaceous,  which,  however,  is  undoubtedly  continuous  beneath  it. 

The  Cretaceous  strata  occupy,  on  Cow  Creek  and  the  small  streams 
adjacent  to  it,  an  area  of  about  twelve  miles  long,  east  and  west, 
and  half  as  much  broad  from  north  to  south ;  the  best  exposures, 
however,  are  on  the  banks  of  Cow  Creek,  twelve  miles  southeast  of 
Shasta  City.  At  this  locality,  beds  of  soft,  buff-colored  sandstones 
alternate  with  thin  shelly  layers,  interstratified  with  argillaceous  shales 
having  a  good  deal  of  sand  mixed  with  them.  The  strata  are  horizon¬ 
tal,  or  with  a  low  dip  away  from  the  mountains,  and  have  evidently  not 
been  disturbed  since  their  deposition.  At  this  locality  the  following 
fossils  were  obtained : 

Baculites  Chicoensis,  Eriphyla  umbonata, 

VoLUTILITHES  NAVARROENSIS,  LlTHOPHAGUS  OVIFORMIS, 

Aporrhais  falciformis,  Leda  translucida, 

Venus  yarians,  Gstrea  Brewerii. 

Of  these,  the  Baculite  was  particularly  abundant.  A  single  Ammonite 
was  obtained,  a  remarkable  contrast,  in  this  respect,  to  the  beds  on  the 
opposite  side  of  the  valley  so  prolific  in  species  of  this  genus. 

A  workable  bed  of  coal  is  reported  as  occurring  on  Cow  Creek,  and 
between  this  and  Clover  Creek.  Mr.  Sanders,  who  opened  the  locality 
on  Clover  Creek,  speaks  of  several  strata,  one  of  which  has  one  foot 
of  good  coal  at  the  surface,  associated  with  three  feet  of  shale.  The 
outcrop  extends,  it  is  said,  for  some  ten  miles  in  a  northwest  direction, 
and  the  locality,  although  probably  of  little  economical  importance  at 
present,  is  interesting  as  indicating^  in  connection  with  many  other 
carbonaceous  deposits  in  the  Cretaceous  strata  of  the  Pacific  coast,  a 
tendency  to  the  formation  of  coal  in  this  region  during  the  accumula¬ 
tion  of  a  system  of  rocks  which,  in  other  parts  of  the  world,  has  gene¬ 
rally  been  remarkably  barren  of  this  substance. 


ALONG  THE  FOOT-HILLS. 


205 


Between  Cow  Creek  and  Bear  Creek,  there  is  a  broad  plain  of  vol¬ 
canic  ashes,  destitute  of  trees,  and  alnfost  hare  of  herbage,  and  as  yet 
hardly  at  all  eroded  into  canons.  On  nearing  Bear  Creek,  more  solid 
lava  makes  its  appearance  and  increases  as  we  pass  south.  These  vol¬ 
canic  materials  are  all  derived  from  the  great  centre  of  eruptive  agen¬ 
cies  at  and  near  Lassen’s  Butte.  The  examination  of  the  region  be¬ 
tween  that  now  extinct  volcano  and  the  Sacramento  Biver  shows,  that 
there  were  a  large  number  of  smaller  volcanoes  once  active  there,  and 
that  these  added  extensively  to  the  mass  of  ejected  materials.  These 
consist  of  layers  of  ashes  and  scoriae,  alternating  with  hard  basaltic 
lava,  and  they  now  cover  a  district  about  a  hundred  miles  long  from 
Pit  River  to  Oroville,  and  nearly  seventy-five  wide. 

Between  the  mouth  of  Bear  Creek  and  Red  Bluff,  the  volcanic  rocks 
come  entirely  down  to  the  river.  They  may  be  well  studied  at  Battle 
Creek,  which  rises  at  Lassen’s  Butte,  and  has  cut  a  deep  canon  in  the 
stratified  lavas,  which  is  in  places  as  much  as  800  feet  deep.  The  ba¬ 
saltic  lava  seems  to  have  flowed  in  sheets  over  the  surface,  forming  a 
regular  slope  from  Lassen’s  Butte  to  the  Sacramento. 

On  the  north  side  of  Battle  Creek,  and  about  ten  miles  east  of  Fort 
Reading,  there  is  a  conspicuous  cone,  rising  from  the  slope  of  lava; 
this  is  figured  in  Dr.  Newberry’s  Report  (Pacific  Railroad  Reports,  Yol. 
VI,  Part  2,  Fig.  26).  Its  altitude,  as  determined  by  our  measurements, 
is  2633  feet  above  the  sea,  or  856  feet  above  its  base.  The  sides  are 
very  steep,  and  form  a  regular  truncated  cone.  The  rim  of  the  crater 
is  perfect,  about  900  yards  in  circumference,  nearly  circular,  and  having 
its  northern  edge  about  100  feet  higher  than  the  opposite  one.  The 
crater  is  funnel-shaped,  and  about  225  feet  deep,  the  sides  steep  and 
covered  with  trees  and  shrubs.  Scoriae  and  pumice  are  abundantly 
scattered  over  the  rim  and  within  the  crater.  Several  other  cones  are 
visible  on  the  south  side  of  Battle  Creek ;  an  outline  of  two  of  which 
is  given  in  the  annexed  wood-cut  (Fig.  31). 

Fig.  31. 

a \ 


VOLCANIC  CONES,  NEAR  BATTLE  CREEK. 


206 


GEOLOGY  OF  THE  SIERRA  NEVADA 


The  volcanic  rocks  evidently  cover  the  Cretaceous  strata,  and  a 
single  specimen  of  a  fine  Ammonite  (. Ammonites  sub  tricar  inatus),  obtained 
by  us  in  that  vicinity,  and  said  to  have  been  found  in  a  boulder  in  a 
deep  gulch  between  Battle  and  Bear  Creeks,  indicates  that,  in  places, 
the  streams  may  have  cut  through  the  volcanic  into  the  sedimentary 
rocks  beneath. 

The  Sacramento  Valley  opens  out  into  a  plain  again  just  below  Bed 
Bluff,  and  at  a  much  lower  level  on  the  east  side,  El  Primer  Canon 
Ranch  being  the  first  one  south  of  the  barren  lava  slopes.  Antelope 
Creek  rises  near  Lassen’s  Butte  and  for  many  miles  cuts  a  deep  canon 
into  the  volcanic,  which  is  in  places  probably  worn  through  into  the 
Cretaceous,  as  fossils  are  reported  to  have  been  found  in  it.  The  canon 
is  very  deep  near  its  mouth,  and  the  bottom  is  in  places  quite  inacces¬ 
sible  ;  it  was  followed  for  several  miles,  without  any  fossils  being  ob¬ 
tained,  the  rock  being  exclusively  volcanic,  forming  cliffs  800  to  1000 
feet  high,  composed  of  alternate  beds  of  basaltic  lava  and  ashes.  The 
materials  forming  the  slopes  near  Tuscan  Springs  seem  to  have  been 
poured  forth  from  the  two  craters  noticed  above. 

At  Tuscan  Springs,  or  Lick  Springs  as  it  was  formerly  called,  the 
Cretaceous  strata  have  been  bent  up  into  a  rather  sharp  arch,  or  anti¬ 
clinal  fold,  and  the  volcanic  rocks  have  been  denuded  in  the  canon,  so 
as  to  expose  the  sedimentary  beds  over  an  area  of  about  one-half  a  mile 
from  northwest  to  southeast,  and  a  mile  in  the  opposite  direction.  The 
springs  are  nearly  in  the  centre  of  this  area,  the  strata  dipping  away 
from  them  in  every  direction,  at  an  angle  of  from  35°  to  45°.  At  the 
springs  the  strata  are  much  bent  and  twisted,  and  the  cracks  which 
have  been  formed  while  these  disturbances  were  going  on  have  become 
filled  with  carbonate  of  lime. 

The  annexed  section  (Fig.  32)  will  serve  to  give  an  idea  of  the  posi¬ 
tion  of  the  strata  at  this  locality,  as  near  as  it  could  be  made  out. 

Where  the  Cretaceous  strata  were  exposed,  they  had  a  much  greater 
dip  than  that  of  the  volcanic  beds  on  each  side,  but  as  the  two  forma¬ 
tions  could  not  be  examined  in  actual  contact  with  each  other,  it  was 
impossible  to  say  decidedly  whether  they  were  really  unconformable. 
West  of  the  springs,  however,  the  Cretaceous  shales  have  a  dip  of  40° ; 
while,  but  a  few  feet  distant,  the  beds  of  volcanic  ash  were  inclined 


ALONG  THE  FOOT-HILLS. 


207 


only  10°  to  15°;  a  similar  condition  of  things  was  observed  on  the  east 
side  also,  so  that  it  would  appear  that  the  disturbance  of  the  underlying 


Fig.  32. 


a 

b 


SECTION  AT  TUSCAN  SPRINGS. 

a ,  a.  Basaltic  lava,  b,  h.  Volcanic  ash  and  scoris®.  c,  c.  Conglomerate,  d,  d.  Cretaceous 

sandstone,  s.  Springs. 


sedimentary  rocks  must  have  commenced  before  the  volcanic  materials 
were  deposited  on  them,  and  that  this  disturbance  still  continued  to  act 
in  the  same  direction  after  that  took  place. 

In  several  places  a  bed  of  conglomerate  separates  the  Cretaceous 
strata  from  the  volcanic ;  this  bed  is  made  up  of  smooth  pebbles  of 
metamorphic  rocks,  chiefly  quartzose,  cemented  by  a  ferruginous  and 
finely  pulverized  material,  as  if  a  thick  detrital  mass,  like  that  of  which 
the  present  auriferous  beds  of  gravel  are  made  up,  had  covered  the  sur¬ 
face  of  the  Cretaceous  before  the  deposition  of  the  volcanic  upon  it. 

Some  of  the  Cretaceous  beds  at  this  locality  are  particularly  rich  in 
fossils,  of  which  a  large  number  were  formerly  collected  by  Dr.  Veatch, 
and  have  been  presented  to  the  Survey.  Among  these  the  most  abun¬ 
dant  and  characteristic  were  : 


Fusus  Averillii, 

Neptunea  ponderosa, 
Perissolax  brevirostris, 
Haydenia  impressa, 

VOLUTILITHES  NAV ARROENSIS, 

Ficus  cypr^eoides,  . 

Gyrodes  expansa, 
Amauropsis  ovieormis, 

ClNULIA  OBLIQUA, 

Architectonica  Veatchii, 
Tessarolax  distorta, 
Aporrhais  ealciformis, 
Turritella  Veatchii, 
Nerita  cuneata, 


Martesia  clausa, 
CORBULA  TrASKII, 
Mactra  Ashburnerii, 
Venus  Veatchii, 
Astarte  Tuscana, 
Modiola  cylindrica, 
Inoceramus  Piochii, 
Trigonia  Trtoniana, 
T.  Evansii, 

Meekia  sella, 

M.  RADIATA, 

Arca  Breweriana, 
Axina£a  Veatchii, 
Nucula  truncata. 


208 


GEOLOGY  OF  TIIE  SIERRA  NEVADA 


The  waters  of  the  Tuscan  Springs  have  considerable  repute  for  their 
medicinal  qualities,  especially  in  the  cure  of  rheumatism  and  syphilitic 
diseases.  The  temperature  (October,  1862)  was  76°.  They  contain 
common  salt,  carbonate  of  soda,  borate  of  soda,  salts  of  lime,  and 
evolve  some  sulphuretted  hydrogen  and  a  large  quantity  of  carburetted 
hydrogen,  which  is  collected,  partially  purified,  and  burned  for  heating 
the  water  under  the  steam  baths.  A  deposit  of  calcareous  tufa  is 
forming  here,  portions  of  which  are  finely  banded,  and  closely  resemble 
the  “  Suisun  marble”  and  the  limestone  found  on  the  west  side  of 
Monte  Diablo. 

On  passing  south  from  Antelope  Creek,  the  plain  widens  out  in 
many  places  and  a  considerable  part  of  it  is  a  treeless  and  nearly  bar¬ 
ren  slope  of  volcanic  ash,  covered  with  great  numbers  of  small  lava 
boulders,  which  extends  out  for  some  distance  from  the  termination  of 
the  basaltic  lavas.  Mill  Creek,  which  comes  down  to  the  plain  between 
Antelope  and  Deer  Creeks,  as  seen  from  the  road,  appears  like  these 
to  have  cut  a  deep  canon  in  the  volcanic  formation,  and  emerges  from 
this  by  a  “  gate,”  conspicuous  for  a  long  distance. 

The  canon  of  Deer  Creek  was  examined  for  some  distance  up,  and  it 
was  found  to  be  cut  deeply  into  the  volcanic  materials,  which  consist  of 
alternating  beds  of  basalt  and  ashes,  forming  terraces  on  both  sides. 
Our  party  was  informed  by  some  “prospecters”  who  had  just  made  an 
examination  of  this  canon  to  its  head,  that  they  had  traced  it  nearly 
back  to  Lassen’s  Butte.,  and  that  it  was  everywhere  in  the  volcanic 
rocks,  and  often  so  precipitous  that  the  stream  could  not  be  reached. 
No  trace  of  gold  was  discovered  in  the  sands  along  the  creek. 

All  along  between  Deer  and  Chico  Creeks  the  lava  terminates  with 
an  abrupt  edge,  and  the  plain  beneath  and  nearest  to  it  is  barren  and 
dry  and  covered  with  volcanic  fragments ;  but  farther  down  towards  the 
river  the  land  becomes  gradually  fertile,  and  has  considerable  timber. 
The  proportion  of  good  agricultural  land  increases  as  we  approach 
Chico  Creek,  where  the  plain  is  about  ten  miles  wide.  This  creek, 
like  the  others  farther  north,  has  worn  a  deep  canon  in  the  volcanic 
rocks,  extending  for  many  miles  back  in  the  mountains.  About  six 
miles  from  the  entrance  of  the  canon,  the  stream  has  cut  through  into 
the  Cretaceous  strata  beneath;  but  the  point  is  very  difficult  of  access, 


ALONG  THE  FOOT-HILLS. 


209 


the  gorge  being  nearly  impassable  in  places  below  and  the  volcanic 
materials  on  each  side  having  an  elevation  of  800  to  900  feet. 

The  Cretaceous  strata  exposed  at  this  place  are  chiefly  sandstones, 
and  they  appear  to  be  quite  horizontal.  They  have  not  been  deeply  cut 
into,  but  some  of  the  beds  are  highly  fossiliferous,  and  specimens  from 
this  locality  have  been  widely  distributed  over  the  country.  Among 
the  species  found  here  are:  Ammonites  Chicoensis ,  Baculites  Chicoensis , 
a  number  of  the  univalve  shells  mentioned  as  characteristic  species  at 
Tuscan  Springs,  including  Volutalitlies  Navarroensis ,  Cinulia.  obliqua ,  and 
Aporrhais  falciformis ,  as  well  as  a  more  abundant  supply  of  bivalves, 
among  which  the  following  are  common  :  Mactra  Ashburnerii ,  Venus  va- 
rians ,  Meretrix  lens ,  M. .  nitida ,  Dosinia  injlata ,  Trigonia  JEvansii ,  Meekia 
navis ,  and  some  others. 

Cretaceous  fossils  are  also  reported  from  the  canon  of  Butte  Creek, 
below  Diamondville,  where  they  are  said  to  be  abundant;  but  the 
locality  is  difficult  of  access. 

At  Pence’s  Ranch,  about  nine  miles  north  of  Oroville,  and  near  the 
southwestern  termination  of  the  great  volcanic  table  which  comes  down 
from  Lassen’s  Butte,  a  tine  exposition  of  the  geological  structure  of  the 
northern  foot-hills  of  the  Sierra  may  be  seen,  and  the  relations  of  the 
volcanic  and  Cretaceous  beds  to  the  auriferous  slates  of  the  <rold  region 
may  be  clearly  recognized.  Table  Mountain  Creek,  or  Mesilla  Val¬ 
ley,  here  leaves  the  volcanic  beds,  which  have  been  denuded  to  the 
southwest,  and  has  worn  a  valley  along  the  junction  between  the  Cre¬ 
taceous  and  the  auriferous  slates;  these  latter  are  seen  to  the  east  of 
the  valley,  having  their  usual  northwest  and  southeast  trend  and  a  high 
dip  to  the  northeast. 

About  one  and  a  half  miles  northeast  of  Pence’s  are  large  outcrops 
of  limestone  interstratified  with  the  auriferous  slates;  it  is,  in  general, 
highly  metamorpliic,  although  traces  of  fossils  are  preserved  in  it,  suf¬ 
ficient  to  show  that  it  was  originally  well  supplied  with  them,  and  that 
they  have  since  become  almost  obliterated  by  the  metamorpliic  action. 
The  best  specimens  were  obtained  near  the  bend  of  a  small  canon 
called  “  West  Branch.”  This  belt  of  limestone  extends  several  miles 
in  a  northwest  and  southeast  direction,  but  it  appears  to  be  broken,  so 
that  it  is  made  up  of  disconnected  masses  not  exactly  in  the  same  line, 


GEOL.  VOL.  I. — 27 


210 


GEOLOGY  OF  THE  SIERRA  NEVADA 


but  near  enough  together  to  form  what  may  be  called,  in  a  general 
way,  one  belt.  Lithologically  it  resembles  the  limestone  of  the  hills 
at  Bass’s  Ranch,  but  it  is  more  completely  metamorphic  than  that, 
although  not  traversed  by  trap  dykes,  as  is  the  case  at  that  locality. 
Portions  of  the  Pence’s  Ranch  limestone  would  make  good  gray  mar¬ 
ble,  and  the  lime  burned  from  it  is  of  good  quality.  Another  smaller 
lenticular  mass,  also  highly  metamorphosed,  occurs  about  half  a  mile 
west  of  the  main  belt.  The  fossils  found  in  these  limestones,  although 
imperfect,  are  sufficient  to  identify  them  as  of  the  same  age  as  those  of 
Bass’s  Ranch,  which  are  pronounced  by  Mr.  Mpek  to  be  carboniferous. 
Productus  semireticulatus  and  Spirifer  lineatus  were  recognized  by  Mr. 
Gabb,  and  a  portion  of  the  rock  is  made  up  of  stems  of  crinoids,  too 
much  obliterated  to  allow  of  their  generic  relations  being  made  out. 

Resting  on  the  upturned  edges  of  the  auriferous  slate  and  limestone 
series,  is  a  mass  of  Cretaceous  strata,  chiefly  sandstones,  having  a  hori¬ 
zontal  position,  or  dipping  slightly  to  the  southwest.  These  have  been 
more  or  less  denuded,  and  outcrops  are  found  in  nearly  all  the  arroyos 
and  ravines.  They  extend  to  the  height  of  about  750  or  800  feet  above 
the  sea.  Some  beds  are  highly  fossiliferous  and  rich  in  a  variety  of 
species  as  well  as  in  numbers.  The  following  are  the  most  abundant 
species  found  in  this  vicinity  : 


Ammonites  Chicoensis, 
Helicoceras  Brewerii, 

H.  declive, 

Ptychoceras  asquicostatus, 

P.  QUADRATUS, 

Baculites  Chicoensis, 
Neptun^ea  ponderosa, 
Perissolax  brevirostris, 
Haydenia  impressa, 
VOLUTALITHES  NAVARROENS1S, 

Gyrodes  expansa, 

ClNULIA  OBLIQUA, 

Chemnitzia  Spillmanni, 


Aporrhais  falciformis, 

CORBULA  TrASKII, 

Anatina  lata, 
Pholadomya  Brewerii, 
Mactra  Ashburnerii, 
Lutraria  truncata, 
Tellina  ooides, 

T.  DECURTATA, 

T.  Ashburnerii, 

Venus  yarians, 
Modiola  cylindrica, 
Meekia  nayis, 

Axin^a  Veatchii. 


No  absolute  contact  of  the  Cretaceous  with  the  auriferous  slates  was 
observed ;  but  the  two  formations  were  seen  in  close  proximity.  Rest- 


ALONG  THE  FOOT-HILLS. 


211 


iim  on  the  Cretaceous  is  a  series  of  sand- 
© 

stone  beds  containing  blue  grains,  inter- 
stratified  with  shales  in  which  are  a  few 
impressions  of  fossil  leaves.  These  beds 
are  similar  in  all  respects  to  the  upper 
Pliocene  strata  north  of  Kirker’s  Pass, 
and  they  are,  in  all  probability,  of  the 
same  age.  They  are  covered,  in  turn, 
by  accumulations  of  volcanic  ashes,  sco¬ 
riae,  and  breccia,  and  over  all  rests  a 
heavy  bed  of  basaltic  lava.  The  Tertiary 
and  volcanic  are  perfectly  conformable, 
but  whether  the  Cretaceous  is  also  con¬ 
formable  to  these  has  not  been  demon¬ 
strated  ;  it  appears  probable  that  it  is 
not,  although  the  disturbances  were  not 
great  in  the  interval  between  the  deposi¬ 
tion  of  the  Cretaceous  and  Tertiary. 

The  Tertiary  beds,  in  places,  contain 
considerable  carbonaceous  matter,  and  at 
one  locality  have  been  prospected  for 
coal.  At  this  place,  which  is  about  six 
miles  north  of  Oroville,  there  are  frequent 
impressions  of  the  leaves  of  exogens,  in 
the  black  shales  a  few  feet  beneath  the 
volcanic  beds,  and  a  few  seams  of  coal. 
The  latter  are  not  sufficiently  thick  to  be 
of  any  value. 

The  annexed  section  (Fig.  33)  will 
serve  to  exhibit  the  relations  of  the  strata 
near  Pence’s  Ranch,  as  described  above. 
This  vicinity  is  not  only  extremely  inter¬ 
esting  to  the  geologist,  as  showing  the 
relations  of  two  very  important  groups 
of  strata  to  each  other,  but  is  remarkably 
picturesque,  the  numerous  table-topped 


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s.  Auriferous  slates.  1,1.  Carboniferous  limestone  belts,  intercalated  in  the  auriferous  slates,  c,  c.  Cretaceous  shales,  nearly  horizontal.  f,f.  Tertiary 
sandstones,  and  shales  with  vegetable  impressions,  o,  o.  Band  of  conglomerate,  above  the  Tertiary,  v,  v.  Ashes  and  tufa,  b,  b.  Hard,  basaltic  lava, 
capping  the  hills  and  forming  “Table  Mountains.” 


212 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


hills,  with  the  deep  canons  between,  giving  a  very  peculiar  character  to 
the  scenery. 


CHAPTER  IX. 

THE  MINING  REGION  OF  CALIFORNIA;  EMBRACING  THE  GREAT 
AURIFEROUS  BELT  ALONG  THE  WESTERN  SLOPE  OF  THE  SIERRA 
NEVADA. 


Section  I. — Preliminary  Remarks. 

We  now  proceed  to  take  up  the  great  metalliferous  belt  of  Califor¬ 
nia,  or  the  western  slope  of  the  Sierra  Nevada,  this  being  the  portion 
of  the  State  which  was  for  a  long  time  the  field  for  much  the  larger 
part  of  the  successful  mining  enterprises  undertaken  on  the  Pacific 
border  of  the  United  States,  and  whose  development  led  to  the  discovery 
and  exploration  of  many  other  highly  important  mineral  regions  in  the 
adjacent  States  and  Territories,  so  that  now  it  is  difficult  to  find  a  range 
of  mountains,  within  the  vast  area  west  of  the  Rocky  Mountain  crest, 
where  traces  of  the  “  prospecter’s”  pick  may  not  be  detected,  while  in 
many  places  large  towns  and  thriving  mining  settlements  have  already 
sprung  up.  The  gold  discoveries  on  the  western  slope  of  the  Sierra 
have  led  directly  to  this  result,  and  it  is  from  the  mines  of  California 
that  nearly  all  the  capital  has  been  obtained,  which  has  been  applied, 
with  immense  energy  and  perseverance  if  not  always  with  skill  and 
judgment,  to  the  opening  of  new  mining  districts,  not  only  within  the 
limits  of  the  State,  but  far  beyond  them,  and  in  all  directions,  from  the 
Colorado,  through  the  Great  Basin,  to  the  Columbia. 

The  auriferous  region  of  California  is  not  exclusively  confined  to  the 
western  slope  of  the  Sierra,  nor  can  any  exact  line  of  division  be  drawn 
separating  the  silver-bearing  districts  from  those  which  produce  gold; 
but  by  fiir  the  larger  portion  of  the  last-named  metal  has  come  and  is 
still  being  obtained  from  the  lower  portion  of  the  flanks  of  that  great 
range,  on  what  may,  therefore,  with  propriety  be  called  the  main 


213 


THE  WESTERN  SLOPE. 

auriferous  belt  of  the  State.  And,  for  convenience,  this  belt  will  be 
taken  up  by  itself  and  made  the  subject  of  the  present  chapter,  while 
the  Higher  Sierra,  or  the  loftier  and  almost  uninhabited  regions  of  the 
crest  of  the  mountains,  will  he  described  in  the  succeeding  one.  Hot 
that  mining  explorations  have  failed  to  extend  themselves  into  these 
snow-covered  and  inhospitable  regions ;  hut,  as  yet,  their  results  have 
rarely  been  such  as  to  warrant  the  hope  that,  under  the  present  condi¬ 
tion  of  things,  there  can  he  anything  developed  in  the  upper  portion  of 
the  Sierra  which  will  at  all  compare  in  importance  with  what  we  know 
to  exist  in  the  auriferous  belt  proper.  For  this  reason,  the  chapter 
relating  to  the  High  Sierra  will  be  found  to  be  devoted,  not  so  much  to 
giving  the  results  of  mineral  explorations  and  the  description  of  abor¬ 
tive  mining  enterprises,  as  to  its  grand  physical  features,  its  stupendous 
scenery,  its  geological  peculiarities,  and  to  such  other  considerations  as 
may  suggest  themselves  in  connection  with  the  necessity  of  traversing 
it  at  various  points  with  roads  and  railroads,  which  are  needed  to  con¬ 
nect  California  with  the  great  mining  region  to  the  east,  as  well  as  the 
still  remoter  States  of  the  Mississippi  Valley  and  the  Atlantic  coast. 

After  giving  what  information  our  means  and  space  will  permit  in 
regard  to  the  physical  geography  and  geology  of  the  High  Sierra,  we 
shall  pass,  in  the  succeeding  chapter,  to  a  description  of  those  portions 
of  the  State  which  form  what  is  generally  known  in  California  as  the 
“  Eastern  Slope,”  or  which  lie  to  the  east  of  the  main  crest  of  the 
Sierra,  including  a  series  of  lofty  mountain  ranges  and  deep  valleys 
between  them,  opening  out  to  the  southeast  into  the  Great  Basin,  or 
the  Great  Desert  of  California,  a  vast  region,  of  whose  geological  fea¬ 
tures  we  can  give,  at  present,  only  a  faint  sketch. 

The  auriferous  belt  spoken  of  above,  and  to  which  the  present  chap¬ 
ter  is  devoted,  may  be  said  to  begin  in  the  neighborhood  of  the  Tejon 
Pass,  and  to  extend  through  the  State  to  its  northern  limit.  Owing  to 
geological  peculiarities,  however,  different  portions  of  the  flanks  of  the 
Sierra  are  of  very  unequal  importance  as  gold-producing  regions. 

The  principal  auriferous  district,  and  that  which  comprises  a  large 
proportion  of  the  population  and  wealth  of  the  State,  occupies  the 
western  portion  of  each  of  the  counties  of  Mariposa,  Tuolumne,  Cala¬ 
veras,  Amador,  El  Dorado,  Placer,  Hevada,  Sierra,  and  Plumas,  with 


214 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


portions  of  the  eastern  sides  of  Yuba  and  Butte,  and  in  describing 
this  region  this  order  will  be  followed  for  convenience,  the  counties 
being  taken  up  in  succession,  from  the  south  towards  the  north.  It  is 
here  that  the. belt  of  metamorphic  slates  and  sandstones,  which  is  pecu¬ 
liarly  the  gold-bearing  formation  of  the  State,  is  developed  to  its  greatest 
width  and  least  concealed  from  the  miner’s  exploration  by  the  presence 
of  overlying  non-metalliferous  formations.  It  is  here,  also,  that  the 
physical  conditions  have  most  favored  the  concentration  of  the  gold  in 
the  detrital  formations,  so  that  it  could  be  obtained  by  simple  washing, 
without  the  necessity  of  mining  for  it  in  the  solid  rock,  and  perhaps 
more  readily  and  more  abundantly  than  in  any  region  ever  opened  to 
seekers  after  the  precious  metal.  The  nature  of  these  conditions, 
which  were  so  favorably  combined  in  California  as  to  enable  the  un¬ 
skilled  mining  population,  which  flocked  thither  from  all  parts  of  the 
world,  to  carry  the  production  of  gold  up  to  between  sixty  and  seventy 
millions  of  dollars  per  annum,  within  three  years  after  the  first  opening 
of  the  country,  will  be  best  explained  and  understood  after  the  geolo¬ 
gical  structure  of  the  region  shall  have  been  described,  and  they  will, 
at  some  future  time,  be  thoroughly  discussed. 

The  limitation  of  the  auriferous  belt  on  the  north,  in  Plumas  and 
Butte  Counties,  is  not  owing  to  the  thinning  out  of  the  proper  gold- 
bearing  formation ;  but,  rather,  to  its  becoming  covered  almost  entirely, 
over  an  immense  area  in  those  counties,  as  well  as  Shasta  and  Siskivou, 
by  a  mass  of  lava  of  very  recent  origin,  which  has  been  poured  forth 
from  Lassen’s  Butte  and  other  volcanic  cones  in  its  vicinity,  and  has 
flowed  over  the  older  slates  and  covered  them  to  a  great  depth  wTith  an 
almost  indestructible  and  entirely  non-metalliferous  formation.  This 
extends  quite  down  to  the  Sacramento  Elver,  near  Antelope  Creek, 
but  recedes  from  it  to  the  east,  beyond  Battle  Creek,  passing  a  little  to 
the  east  of  Fort  Beading.  The  western  edge  of  the  great  volcanic 
plateau  may  be  traced  in  a  line  nearly  northeast  from  that  point,  for  a 
distance  of  about  twenty-five  miles ;  it  then  bends  to  the  northwest 
and  follows  nearly  that  course  to  the  north  line  of  the  State,  passing  a 
little  to  the  east  of  Yreka. 

To  the  west  of  the  volcanic  plateau,  in  portions  of  the  counties  of 
Siskiyou,  Bel  Korte,  Klamath,  and  Trinity,  there  is  a  very  large  area 


THE  WESTERN  SLOTE. 


215 


covered  by  the  auriferous  slates  in  part;  but  where  granite  and  granitic 
or  gneissoid  rocks  are  more  extensively  developed  than  in  the  more 
southern  part  of  the  gold  region;  hence  the  importance  of  this  north¬ 
western  corner  of  the  State  as  a  mining  district  is  less  than  it  would 
otherwise  be,  as  the  granitic  formation  is,  on  the  whole,  considerably 
less  productive  in  gold  than  are  the  slates ;  so  that,  while  the  latter 
rock  may  be  presumed  to  be  auriferous,  until  it  is  proved  to  the  con¬ 
trary,  the  granite,  on  the  other  hand,  cannot  be  expected  as  a  matter  of 
course  to  contain  rich  quartz  veins,  or  to  have  given  origin  by  its  disin¬ 
tegration  to  a  detritus  which  can  be  washed  for  gold  with  profit;  such 
cases  do  occur,  but  they  are  exceptional,  and  the  auriferous  veins  in 
the  granite  are  almost  entirely  limited  to  the  vicinity  of  the  metamor- 
phic  slates  and  sandstones.  Besides,  the  physical  conditions  in  the 
northwestern  corner  of  the  State  are  less  favorable  than  they  are  in  the 
central  mining  counties,  while  its  extreme  roughness,  its  distance  from 
a  market,  and  the  warlike  character  of  the  Indians,  who  have  posses¬ 
sion  of  a  considerable  part  of  this  area,  are  all  drawbacks  to  its  devel¬ 
opment. 

In  the  extreme  southern  portion  of  the  gold  region  beyond  Mariposa 
County,  the  slates  almost  cease  to  form  a  continuous  belt,  and  they  are 
more  and  more  encroached  on  by  the  granite,  as  we  go  towards  the 
Tejon.  In  fact,  there  is  a  gradual  decrease  in  the  width  of  the  aurifer¬ 
ous  formation  proper  froln  the  north  towards  the  south,  and  a  constant 
increase  in  the  amount  of  metamorphism  displayed,  the  granite  occu¬ 
pying  a  larger  portion  of  the  mass  of  the  Sierra,  and  descending  lower 
down  on  its  flanks,  while  the  crest  of  the  mountains  becomes  more  and 
more  elevated,  its  culminating  points  being  in  about  the  latitude  ot 
Owen’s  Lake. 

There  is  a  district  there,  between  the  T^jonPass  and  the  commence¬ 
ment  of  the  gold  region  proper  in  Mariposa  County,  which  might  per¬ 
haps  with  equal  propriety  be  described  in  the  chapter  devoted  to  the 
High  Sierra,  or  in  this  one,  which  embraces  the  auriferous  belt.  On 
the  one  hand,  the  region  in  question  is  chiefly  granitic,  the  metamor- 
pliic  slates  occupying  but  a  few  patches  in  the  granite,  of  very  insignifi¬ 
cant  area  as  compared  with  the  mass  of  the  last-mentioned  rock.  But, 
again,  as  there  are  both  quartz  and  placer  mines  at  various  points 


216 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


through  this  region,  and  as  our  remarks  are  necessarily  of  the  most 
general  character,  our  opportunities  for  its  exploration  having  been 
exceedingly  limited,  it  will  perhaps  be  as  well  to  let  what  we  have  to 
say  in  regard  to  the  district  in  question  precede  the  description  of  the 
main  metalliferous  belt  of  the  Sierra,  which  will  be  taken  up  by  coun¬ 
ties,  and  in  geographical  order  from  north  to  south. 


Section  II. — From  Tsjon  Pass  to  Mariposa. 

In  entering  the  Sierra  Nevada  from  the  Desert,  or  Great  Basin,  by 
Fremont’s  Pass,  which  was  the  route  followed  by  our  party,  a  low  ridge 
is  crossed,  and  the  valley  of  Oak  Creek  is  reached.  After  leaving  the 
beds  of  gravel  and  detritus  which  form  the  edge  of  the  desert,  the  first 
rock  encountered,  at  the  entrance  of  the  pass,  is  a  white  limestone, 
crystalline,  but  distinctly  stratified,  having  a  north-northeast  strike, 
and  a  high  dip  to  the  southeast.  It  seems  to  form  a  narrow  belt,  but 
was  not  minutely  examined.  After  crossing  the  limestone,  soft  granite 
was  observed,  which  rock  continues,  beyond  Oak  Creek,  nearly  to  the 
Tahicliipi  Valley.  Fremont’s  Pass,  or  that  by  which  Fremont  entered 
the  Great  Basin,  in  1844,  is  over  a  low  hill  and  leads  out  from  a  side- 
valley  of  the  Tahicliipi ;  the  name  is  not  used  by  the  settlers,  but  that 
of  Tahicliipi  (Tah-ee-chay-pah  of  the  Pacific  Railroad  Reports)  is  given 
to  the  whole  region  between  the  valley  of  that  name  and  the  desert. 
The  ridge  between  Oak  Creek  and  the  Tahicliipi  Valley  is  chiefly  of 
granite,  with  some  liighly-crystalline,  metamorphic  rock ;  it  is  quite 
low,  being  only  a  few  hundred  feet  above  the  plain. 

Tahicliipi  Valley  is  a  basin  about  eight  miles  long  and  of  irregular 
width,  entirely  surrounded  by  mountains,  of  which  the  highest  rise  to 
nearly  7000  feet  above  the  sea;  the  valley  itself  is  4000  feet  in  elevation. 
At  its  eastern  angle,  in  the  lowest  part  of  the  basin,  is  a  salt  lake,  near 
which,  and  on  its  north  side,  along  White  Rock  Creek,  are  white  strata, 
supposed  to  be  of  volcanic  origin.  North  and  northeast  of  the  valley 
is  a  chain  of  high  and  rugged  mountains,  estimated  at  7000  feet  in  alti¬ 
tude,  and  believed  from  their  appearance  in  the  distance  to  be  volcanic. 
On  the  southwest  is  a  high  granite  mountain,  which,  in  May,  1863,  was 


THE  WESTERN  SLOPE. 


217 


covered  with  snow  and  was  estimated  at  over  7000  feet  high.  Some 
boulders  of  limestone  were  found  in  the  arroyos  that  come  down  the 
sides  of  this  ridge,  and  gold  is  reported  as  existing  in  small  quantities. 
Some  of  the  gravel  in  the  valleys  extending  west  into  the  granite  range 
is  said  to  he  sufficiently  auriferous  to  pay  for  working.  Hydraulic 
mining  is  practised  here  with  some  success,  and  ordinary  placer  wash¬ 
ings  are  carried  on,  at  intervals,  during  the  season  when  water  is  to  he 
had.  The  principal  drainage  of  this  valley  is  by  a  stream,  without  a 
name,  which  leaves  the  basin  at  its  southeast  angle,  and  which  the  Ta- 
hichipi  Pass  follows ;  but  the  Tahicliipi  Creek  is  a  stream  rising  in  the 
western  part  of  the  valley  and  flowing  northwest,  through  a  deep  canon 
in  the  granite,  to  the  Tulare  Plain.  This  would  he  the  lowest  route 
across  the  Sierra  Nevada  into  the  Great  Basin  from  the  Central  Valley 
of  California,  if  a  road  were  made  up  Tahicliipi  Creek ;  hut,  up  to  the 
present  time,  there  is  no  communication  into  the  valley  from  the  west, 
except  by  means  of  a  road  passing  over  a  mountain  which  is  much 
higher  than  the  main  divide  itself.  Lieutenant  Williamson  followed 
down  the  Tahicliipi  Creek  for  flfteen  and  a  half  miles  through  this 
canon,  and  found  it  to  have  an  average  descent  of  157  feet  to  the  mile. 
From  his  description  of  this  pass,  there  would  seem  to  be  no  doubt  that 
it  is  the  easiest  one  by  which  the  Sierra  can  be  crossed ;  but  it  may  he 
considered  doubtful,  from  its  geographical  position  with  regard  to  the 
mining  region  of  the  State,  whether  it  will  ever  become  of  any  great 
importance.  From  the  eastern  entrance  of  this  pass  across  to  the  Col¬ 
orado  is  a  region  very  forbidding  to  settlers  and  railroad  engineers. 
The  elevation  of  the  summit  of  the  pass,  which  is  in  the  valley,  is  given 
by  Williamson  at  4020  feet. 

Tahicliipi  Valley  was  covered  with  excellent  grass  and  forage  when 
visited  by  our  party  (May,  1863),  affording  the  best  pasturage  seen  over 
any  area  of  equal  size  during  the  year’s  journey  among  the  Sierras. 
There  are  a  few  settlers  here  engaged  in  raising  stock,  and  it  is  said 
that  but  little  snow  falls  in  the  valley.* 

*  In  regard. to  the  orthography  of  the  name  which  we  have  written,  “Tahichipi,”  it 
may  be  stated  that,  to  avoid  confusion,  we  have  followed  the  spelling  of  the  United  States 
Surveyor-General’s  Office.  It  comes  pretty  near  the  pronunciation  adopted  by  the  set¬ 
tlers;  perhaps  “Tahachipi”  would  be  still  nearer. 

GEOL.  VOL.  I. — 28 


218 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


At  the  northern  edge  of  the  valley,  and  on  the  east  side  of  Tahichipi 
Creek,  white  crystalline  limestone  occurs,  containing  some  graphite ; 
its  trend  could  not  he  determined.  It  is  cut  through  by  a  wide  dyke 
of  basaltic  lava,  which  runs  nearly  north  and  south. 

From  Tahichipi  Valley  down  the  creek  of  the  same  name,  to  its 
junction  with  Cottonwood  Creek,  granite  and  gneiss  are  the  predomi¬ 
nating  rocks ;  hut  some  mica-slate  was  observed,  especially  near  the 
mouth  of  the  canon,  where  it  forms  rounded  hills  bordered  by  the 
Tertiary  of  the  Tulare  Plain.  The  strike  of  the  gneiss,  which  makes 
up  the  larger  portion  of  the  formation,  is  nearly  north  and  south,  and  it 
dips  at  a  high  angle  to  the  east,  being  much  contorted  and  often  cut 
by  veins  of  milk-white  quartz,  which  run  at  right-angles  to  the  strike 
of  the  inclosing  rock ;  some  of  these  quartz  veins  are  of  very  large 
size.  The  trail  at  present  used,  in  going  from  the  valley  over  to  Cot¬ 
tonwood  Creek,  is  very  rough,  hut  affords  magnificent  views  of  the 
surrounding  mountains  and  the  Great  Valley. 

From  Cottonwood  Creek,  our  party  crossed  over  to  Walker’s  Basin, 
“  the  Park”  of  the  Pacific  Railroad  Reports.  The  trail  led  up  Cotton¬ 
wood  Creek  and  Pass  Creek,  a  branch  of  the  first-named,  and  then 
over  a  sharp  and  steep  ridge,  the  rocks  being  exclusively  gneiss  and 
mica^slate,  the  former  predominating.  There  is  considerable  soil  on 
the  ridge,  and  a  pretty  good  growth  of  timber.  In  the  canon  of  Pass 
Creek  are  many  boulders  of  limestone,  indicating  a  considerable  mass 
of  this  rock  somewhere  to  the  east. 

Walker’s  Basin,  or  Valley,  is  a  triangular  area  surrounded  on  all 
sides,  except  a  portion  of  the  southeast,  by  high  mountains,  the  highest 
peaks  east  and  west  being  fully  7000  feet  in  altitude.  Canon  Moun¬ 
tain,  on  the  west,  has  very  large  exposures  of  bare  rock,  consisting  of 
granite  and  gneiss,  beautifully  and  distinctly  bedded  or  stratified,  with 
a  strike  of  R.  75°  E.,  and  a  nearly  vertical  dip.  The  high  mountain 
lying  northeast  of  the  valley  is  of  the  same  character,  with  rather  more 
granite,  having  a  north-northwest  strike  and  northeast  dip.  The  im¬ 
mense  areas  of  bare  and  rugged  rock  on  these  peaks  give  a  peculiar 
grandeur  to  the  landscape,  especially  as  contrasting  with  the  green  her¬ 
bage  and  spring  vegetation  of  the  level  region  below.  The  soil  of  the 
valley  or  basin  is  sandy,  and  chiefly  made  up  of  granitic  detritus;  but 


TIIE  WESTERN  SLOPE. 


219 


it  produces  large  crops,  in  localities  where  there  is  a  sufficient  quantity 
of  water.  Boulders  of  limestone  are  abundant  in  this  region,  and  a 
large  ridge  of  this  rock  is  said  to  occur  four  or  five  miles  east  of  the 


valley.  The  outlet  of  Walker’s  Basin  is  at  its  southeast  corner,  where 
the  stream  enters  a  deep  and  narrow  canon,  through  which  it  threads 
its  way  for  twelve  or  fifteen  miles,  to  reach  the  Tulare  Valley. 

A  low  divide,  perhaps  1000  feet  above  the  general  level  of  Walker’s 
Basin,  separates  it  from  the  valley  of  Kern  River.  In  the  ridge  are 
mica-slate  and  gneiss,  trending  about  K.  60°  W.,  and  dipping  at  a  high 
angle,  sometimes  north  and  sometimes  to  the  south.  These  rocks  con¬ 
tinue  along  the  trail,  nearly  to  Kern  River,  and  some  granite  is  asso¬ 
ciated  with  them.  Kear  the  foot  of  the  trail,  on  entering  the  valley  of 
the  Kern,  the  slates  are  observed,  in  decomposing,  to  form  a  dark-red, 
ferruginous  soil,  like  that  of  the  auriferous  belt  of  the  Sierra;  but  this 
detritus  has  not  proved  to  contain  gold. 

On  the  east  side  of  the  trail  are  high  mountains,  with  bold  and  pre¬ 
cipitous  sides,  made  up  of  light-colored  granite.  The  higher  ridges  of 
this  region  are  very  barren,  and  only  thinly  wooded.  From  the  sum¬ 
mit  of  the  trail  there  is  an  extensive  view,  over  a  region  of  rugged 
granite  mountains  lying  to  the  north  of  Kern  River,  which  are  very 
barren  and  have  but  little  timber  on  them. 

Walker’s  Pass  crosses  the  Sierra  near  the  point  where  the  Kern 
River  bends  from  its  southerly  course,  and  runs  west  across  the  ranges 
to  enter  the  Tulare  Plain.  The  wagon-road  from  the  valley  does  not, 
however,  follow  the  river,  but  crosses  a  high  mountain  range  to  the 
north  of  it,  as  the  river  itself  flows,  for  a  portion  of  the  distance,  in  an 
inaccessible  canon  with  almost  vertical  walls. 

Keysville  is  situated  at  the  forks  of  the  river,  and  two  miles  above 
this  the  canon  opens  out  into  a  broad  valley,  similar  to  Walker’s  and 
the  Tahichipi  Basins.  The  Korth  Fork  flows  into  this  valley,  having  pur¬ 
sued  a  southerly  course,  between  two  parallel  ranges  of  the  Sierra,  from 
its  head,  a  little  west  of  Owen’s  Lake.  Granite  is  the  predominating 
rock  of  the  region  around  Keysville,  and  no  other  is  seen  for  six  miles 
east.  At  this  distance,  going  in  that  direction,  limestone  is  met  with, 
associated  with  mica-slates  and  quartzites,  undoubtedly  of  metamorphic 
origin.  The  limestone  is  crystalline,  and  has  numerous  dark  bands 


220 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


parallel  with  the  stratification,  which  give  it  a  very  elegant  appearance. 
The  strike  is  H.  15°  to  25°  W.,  and  the  dip  vertical,  or  at  a  high  angle 
to  the  southwest.  Another  locality  of  metamorphic  rock  is  at  “  Ro¬ 
berts’s,”  about  twenty  miles  east  of  Keysville,  where  there  is  an  ex¬ 
posure  of  hornblende-slate  of  limited  extent.  With  this  exception, 
granite  was  the  only  rock  seen  in  the  region.  This  has  a  distinctly 
bedded  structure,  so  that  when  seen  in  large  masses  it  appears  as  if 
stratified ;  it  is  also  more  or  less  cut  by  veins  of  lighter  granite  of  some, 
what  different  texture  and  composition.  Mountains  rise  on  each  side 
of  the  valley  to  the  elevation  of  about  7000  feet,  having  sparsely  scat¬ 
tered  timber  on  their  sides.  The  soil  at  their  base  is  made  up  of 
granitic  detritus. 

Walker’s  Pass  follows  up  a  small  branch  of  the  Kern,  called  on  the 
Pacific  Railroad  Map  the  Chay-o-poo-ya-pah ;  the  elevation  of  the  sum¬ 
mit  of  the  pass  is  given  by  Williamson  at  5302  feet,  and  the  route  is 
pronounced  by  him  unfavorable  for  a  railroad,  as  the  rise  of  the  last 
eight  miles,  in  going  from  the  west  to  the  summit,  is  very  steep, 
averaging  over  300  feet,  and  being  for  the  last  mile  and  a  half  as  much 
as  428  feet,  per  mile.  The  mountains  rise  on  each  side  of  the  pass  to 
the  height  of  from  5000  to  7000  feet.  Hornblende-slate  occurs  on  the 
north  side,  lying  on  the  granite,  and  dipping  to  the  northeast;  but 
granite  is  everywhere  the  predominating  rock.  From  the  summit  of 
the  pass  there  is  a  gradual  slope  to  the  desert.  A  great  basin,  or  open 
plain,  extends  between  the  Sierra  and  the  Coso  Mountains,  which  lie 
some  eighteen  or  twenty  miles  to  the  east.  The  detrital  materials 
forming  this  plain  sink  in  a  gradual  slope  towards  the  centre  from  the 
ranges  on  each  side ;  but  the  western  side,  or  that  reposing  on  the 
Sierra,  rises  much  the  highest  and  forms  great  tables  against  the  moun¬ 
tains,  rising  to  a  height  of  at  least  4500  feet  above  the  sea.  As  far  as 
the  composition  of  this  detrital  mass  could  be  observed,  it  appeared  to 
be  made  up  of  gravel  and  coarse  granitic  sand,  but  did  not  contain 
many  large  boulders.  It  is  cut  by  deep  gorges,  which  are  occupied  by 
running  water  only  at  the  time  of  heavy  rains.  The  gravel  is  not  con¬ 
solidated  into  a  rock,  and  whether  it  belongs  to  the  Tertiary  or  to  a 
Post-Tertiary  formation  is  not  positively  known.  Along  its  western 
border,  at  the  base  of  the  Sierra,  many  bare  and  ragged  outcrops  of 


THE  WESTERN  SLOTE. 


221 


granite  project  above  the  detrital  masses  for  hundreds  of  feet,  giving  a 
peculiarly  and  grandly  picturesque  effect  to  the  desolate  landscape. 

The  mining  district  of  “  Slate  Range”  lies  about  55  miles,  in  the 
direction  of  K.  79°  E.,  from  the  eastern  entrance  of  Walker’s  Pass,  in 
the  second  range  of  mountains  to  the  east.  This  region  has  not  yet 
been  examined  by  the  Survey. 

From  the  forks  of  Kern  River  west,  the  road  does  not  follow  the 
river,  but  crosses  the  mountains  to  the  north.  About  Iveysville  the  for¬ 
mation  is  entirely  granite,  generally  very  hard;  it  is  traversed  by  dykes 
of  the  same  rock,  but  having  a  different  texture,  and  also  by  quartz 
veins,  of  which  the  direction  is  approximately  northeast  and  south¬ 
west.  Some  of  these  are  worked;  one  called  the  “  Mammoth  Ledge,” 
about  one  mile  southeast  of  Keysville,  is  a  well-defined  vein,  running 
about  northeast  and  southwest,  and  dipping  vertically ;  it  is  said  to  pay 
well,  and  has  several  claims  located  on  it.  The  wall-rock  is  exclusively 
granitic.  Another  vein  is  reported,  ten  or  eleven  miles  northeast 
of  Keysville,  which  is  said  to  be  wide  and  productive.  Rich  speci¬ 
mens  of  auriferous  arsenical  pyrites  have  been  brought  to  the  office  of 
the  Survey  from  this  region,  and  preparations  were  making,  a  year 
ago,  to  open  extensive  mines  on  the  lodes.  There  are  also  some  gold- 
washings  in  the  granitic  detritus. 

The  road  from  Keysville  to  the  Tulare  Valley  passes  over  Greenhorn 
Mountain,  and  is  very  steep  and  difficult.  The  rock  is  all  granitic, 
with  numerous  placer  mines,  some  claims  paying  very  well.  There  are 
quartz  veins  in  the  granite,  generally  in  the  neighborhood  of  these 
placers ;  but  occasionally  there  are  gulches,  quite  productive  in  gold, 
and  near  which  no  quartz  is  found.  The  diggings  increase  in  number 
as  we  approach  White  River.  All  the  streams  coming  down  from  the 
Sierra  pass  through  narrow  canons  before  entering  the  Tulare  Plain; 
this  renders  it  impossible  to  ascend  into  the  mountains  by  following  up 
the  valleys.  But  in  the  interior  of  the  chain,  after  passing  the  out¬ 
side  ridges,  the  canons  open  out  into  comparatively  broad  valleys,  some 
of  which  are  very  charming,  as  contrasted  with  the  wild  and  desolate 
region  around  them.  Pose  Flat,  Little  Pos<$  Flat  and  Linn’s  Valley 
are  instances  of  these  openings.  The  western  side  of  the  chain  has 
much  more  timber  than  the  eastern.  Over  Greenhorn  Mountain  and 


222 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


to  the  east  of  it,  three  species  of  oaks  and  two  of  pines  are  common 
trees;  there  are  many  shrubby  and  herbaceous  plants,  and  an  abundance 
of  forage. 

The  road  from  Keysville  to  Tulare  Valley  does  not  emerge  from  the 
hills  until  it  nearly  reaches  the  Tide  River.  Between  Tide  and  AVhite 
Rivers,  it  passes  for  some  miles  among  low,  rounded  granite  knobs, 
the  Tertiary  tables  being  very  conspicuous  in  front,  the  rounded  tops 
of  the  almost  innumerable  hills  rising  to  nearly  the  same  elevation, 
and  gradually  declining  towards  the  centre  of  the  Tulare  Valley. 

On  emerging  into  the  plains  near  TuR  River  an  outer  tier  of  low 
hills  with  rounded  summits  was  observed;  they  were  composed  of 
metamorphic  rocks,  and  chiefly  of  slates.  This  belt  continues  to  the 
northwest,  rising  into  hills  of  considerable  height  between  Tule  River 
and  Four  Creeks;  but  they  do  not  form  a  continuous  ridge,  as  the 
plain  in  some  places  extends  back  to  the  granite.  This  band  of  rock 
appears  to  be  the  same  which  appears  in  the  T£jon  Canon  in  the  form 
of  mica-slate. 

From  Visalia  to  Fort  Miller,  the  route  of  our  party  was  along  the 
line  of  the  horizontal  Tertiary  beds,  which  form  the  lowest  belt  of  foot¬ 
hills  at  the  base  of  the  Sierra;  these  will  be  found  noticed  in  the  pre¬ 
ceding  chapter.  The  region  behind  these  elevations,  higher  up  oii  the 
flanks  of  the  mountains,  is  but  little  known.  The  streams  have  been 
carefully  prospected  by  explorers,  no  doubt,  as  it  has  rarely  hap¬ 
pened  that  even  the  most  insignificant  gulch  has  escaped  the  notice  of 
the  gold-seekers,  along  the  whole  western  slope  of  the  Sierra ;  the  ab¬ 
sence  of  mining  camps  through  this  region,  therefore,  is  pretty  strong 
evidence  that  the  rocks,  even  if  auriferous  in  places,  are  not  generally 
and  sufficiently  so  to  be  worthy  of  continuous  working  under  present 
conditions.  It  is  desirable,  however,  that  farther  explorations  should  be 
made  by  the  Survey  in  this  district,  not  only  for  geological  purposes, 
but  for  the  sake  of  getting  a  better  idea  of  the  topography,  which  is 
known  only  in  its  rudest  outlines.  Some  notices  of  localities  of  gold- 
washings  high  up  on  the  streams  which  come  down  into  the  plain 
along  this  part  of  the  Sierra  will  be  found  in  the  next  chapter. 


TIIE  WESTERN  SLOPE  —  MARIPOSA  COUNTY. 


223 


Section  III. — Mariposa  County. 

The  County  of  Mariposa  comprises  the  region  drained  by  the  Merced 
River  and  its  very  numerous  branches.  The  line  between  this  and 
Tuolumne  County  on  the  north  follows  the  divide  between  the  Merced 
and  the  Tuolumne  Rivers  nearly  to  their  heads,  an  east  and  west  line 
running  across  to  Mono  Lake,  forming  the  north  boundary;  the  south¬ 
eastern  is  a  straight  line  drawn  from  the  head  of  the  Chowchilla  River 
to  meet  this  at  the  lake.  The  county  as  thus  bounded  is  about  sixty- 
live  miles  long  in  a  northeast  and  southwest  direction,  and  thirty  miles 
wide.  Mariposa  County  does  not  extend  to  the  San  Joaquin  River;  it 
reaches  no  farther  in  that  direction  than  the  lower  edge  of  the  foot-hills 
of  the  Sierra,  where  it  meets  the  line  of  Merced  County. 

The  settlements  in  Mariposa  County  are  almost  exclusively  confined 
to  its  lower  or  southwestern  side.  There  is  no  wagon -road  across  the 
Sierra  leading  through  the  county;  but  there  is  a  trail,  over  the  so- 
called  Mono  Pass,  which  is  a  good  deal  used  during  the  summer  by 
pack-trains.  The  business  is  not  sufficient  to  create  settlements  along 
this  route,  as  there  was  not,  in  1863,  a  house,  or  cabin  even,  between 
the  Yosemite  Valley  and  the  eastern  base  of  the  Sierra. 

For  a  description  of  the  magnificent  scenery  of  the  upper  part  of 
this  county,  as  well  as  of  the  physical  features  of  its  higher  portion, 
reference  may  be  made  to  the  succeeding  chapter.  The  present  one 
has  to  do  only  with  the  lower  mining  portion  of  the  county,  of  which, 
however,  it  will  be  necessary  to  give  only  the  briefest  possible  descrip¬ 
tion,  as  our  materials  are  far  from  complete,  and  space,  in  this  volume, 
is  very  limited. 

The  great  feature  of  Mariposa  County  is  the  so-called  “  Mariposa 
estate,”  on  which  are  several  of  the  largest  mines  in  the  State,  and 
where  extensive  improvements  have  been  made,  a  large  amount  of 
money  expended,  and  which,  on  many  accounts,  has  attracted  a  very 
considerable  share  of  attention  on  both  sides  of  the  Atlantic.  This 
estate  comprises  an  area  of  seventy  square  miles,  and  extends  from  the 
Merced  River  southeast  for  about  sixteen  miles,  keeping  on  the  line  of 


224 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


the  great  quartz-lodes  of  this  region ;  this  direction  is  also  nearly  that 
of  the  strata  in  wliicli  the  veins  are  inclosed.  Placer  mining  has  been 
carried  on  here  since  the  earliest  days  of  mining  enterprise  in  Califor¬ 
nia,  and  it  was  here  that  quartz-mining  was  first  attempted,  as  early  as 
1852.  The  magnitude  of  the  outcrops  of  quartz  and  the  rich  yield  of 
gold  of  some  of  the  lodes,  especially  near  the  surface,  might  well  turn 
public  attention  in  this  direction,  and  give  rise  to  hopes  of  boundless 
wealth  to  be  realized  from  their  working,  which  have  thus  far  not  been 
satisfied. 

The  geology  of  the  Mariposa  estate  has  been  examined  with  some 
detail  by  Mr.  King,  from  whose  notes  the  following  notice  of  some  of 
the  most  prominent  facts  connected  therewith  is  chiefly  taken. 

The  topographical  features  of  the  estate  are  strictly  subordinate  to 
the  geological  structure,  the  courses  of  the  streams  and  mountains 
being  all  in  the  main  parallel  with  the  normal  direction  of  the  strata; 
the  streams,  however,  as  is  so  often  the  case  on  the  Pacific  coast,  do 
not  fail  occasionally  to  show  their  independence  of  the  ridges,  by 
breaking  through  them  at  right-angles  to  their  general  trend.  The 
northeastern  boundary  of  the  estate  is  a  lofty  and  precipitous  range  of 
mountains,  known  as  the  “Mount  Bullion  Range this  is  a  very 
conspicuous  feature  in  the  topography  of  the  country,  through  the 
northern  half  of  the  estate,  but  it  falls  ofi*  to  the  south  and  runs 
into  several  parallel  lower  ranges,  between  which  flow  the  branches  of 
Stockton  and  Mariposa  Creeks.  Parallel  with  this  range,  and  next 
southwest,  is  the  main  valley  of  the  estate,  Bear  Valley,  with  a  stream 
of  the  same  name,  which  flows  southeast  nearly  to  the  centre  of  the 
tract  and  then  turns  and  breaks  through  the  mountains  on  the  south¬ 
west,  called  Juniper  Ridge.  Crossing  the  low  divide  which  separates 
Bear  Valley  from  the  Agua  Fria,  we  find  the  southeastern  portion  of 
the  estate  occupied  by  short,  broken  ridges,  through  which  the  Agua 
Fria  Creek  winds  its  way,  keeping  a  general  southeast  direction,  with 
many  bends  at  right-angles  to  this. 

Through  the  centre  of  the  estate,  in  the  portion  occupied  by  Bear 
Valley  and  the  Agua  Fria,  is  a  broad  belt  of  slates,  which  is  the  main 
geological  feature  of  the  region.  On  each  side  of  this  are  belts  of 
sandstone,  mostly  in  a  highly  metamorphic  condition ;  these  have  ag’ain 


THE  WESTERN  SLOPE  —  MARIPOSA  COUNTY. 


225 


masses  of  slate  outside  of  them,  but  of  which  only  very  small  corners 
fall  within  the  limits  of  the  Mariposa  grant.  Subordinate  to  these  belts 
of  sandstone  and  slate  are  masses  of  serpentine  and  beds  of  limestone. 
The  extreme  southern  end  of  the  estate  is  occupied  by  granite,  which 
cuts  across  the  other  formations  and  continues  westward  towards  the 
foot-hills. 

The  upper  or  northeastern  sandstone  range  has  its  maximum  of  ele¬ 
vation,  as  well  as  of  metamorphic  condition,  towards  the  centre  of  the 
estate,  in  the  lofty  ridge  of  Mount  Bullion,  of  which  the  culminating 
point  is  said  to  be  about  5300  feet  above  the  sea,  Near  the  Merced 
River,  and  towards  the'  town  of  Mariposa,  the  sandstone  is  in  many 
places  very  little  altered  from  its  original  condition.  Along  the  south¬ 
ern  edge  of  the  sandstone  belt,  and  separating  it  from  the  slates,  is  a 
band  of  serpentine,  of  varying  width,  which  is  seen  along  the  base  of 
Mount  Bullion,  and  from  Bullion  Knob  southeast  to  Buckeye  Ridge  and 
the  Crow’s  Nest.  Connected  with  the  serpentine  are  other  magnesian 
rocks,  such  as  steatite  and  talcose  slates.  Two  smaller  outcrops  of  ser¬ 
pentine  appear  near  Mount  Ophir  and  Green  Gulch  Mill ;  these  are 
within  the  slate  belt,  and  they  pass  into  it  through  an  intermediate 
stage  of  talcose  slate.  Within  the  sandstone  series  are  two  unimpor¬ 
tant  outcrops  of  limestone;  one  near  Oak  Springhouse,  the  other  close 
by  the  Benton  Mills.  These  are  both  highly  crystalline,  and  probably 
contain  considerable  silica.  They  coincide  in  strike  and  dip  with  the 
surrounding  rocks. 

Mr.  King  examined  the  strike  of  the  slates  on  this  estate  in  a  great 
number  of  places,  and  found  that  all  the  strata  between  Mount  Ophir 
and  Pine  Tree  have  a  direction  of  N.  28°  W.,  not  varying  anywhere 
more  than  a  decree  and  a  half  from  this.  But  north  of  Pine  Tree  and 
south  of  Mount  Ophir,  the  trend  of  the  slates  is  N.  54°  W.,  showing 
the  existence  of  two  great  breaks  or  flexures  in  the  strata,  with  a 
change  of  direction  of  26°  at  each  of  them.  In  the  vicinity  of  these 
points  where  the  change  takes  place,  the  rocks  are  exceedingly  broken 
and  crushed,  as  would  have  been  expected,  the  surface  rock  having 
every  possible  direction,  and  dipping  at  all  angles,  although  invariably 
to  the  east.  The  length  of  that  southern  portion  of  the  belt  which  has 
a  trend  of  N.  54°  W.,  is  seven  and  one-eighth  miles;  of  that  which 


OF.OL.  VOL.  T. — 29 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


226 

strikes  N.  28°  W.,  live  and  six-eighths  miles.  The  northern  trend  of  N. 
54°  W.  continues  beyond  the  limits  of  the  estate  to  an  indefinite  dis¬ 
tance. 

Within  the  slate  formation  are  interstratified  sandstones,  which  are 
in  some  cases  very  distinctly  bedded,  as,  for  instance,  on  the  west  slope 
of  Hell  Hollow.  The  beds  are  often  several  feet  in  thickness,  and,  like 
the  slates  themselves,  in  all  stages  of  alteration,  as  is  made  evident  by 
the  differences  of  hardness,  color,  and  texture  which  they  exhibit.  The 
region  of  least  metamorpliism  seems  to  have  been  from  the  Pine  Tree 
Mine  west  to  the  slope  of  Juniper  Ridge,  and  southward  to  near  the 
village  of  Bear  Valley.  It  was  in  this  region  that  Mr.  King  found,  in 
situ ,  fossils  by  which  the  age  of  this  formation  was  clearly  made  out  to 
be  Jurassic.* 

As  the  slates  continue  southward,  they  appear  to  become  more  altered, 
and,  in  the  vicinity  of  the  granite,  they  are  very  hard,  and  often  con¬ 
tain  acicular  crystals  of  black  hornblende.  Besides  the  beds  of  sand¬ 
stone  in  this  belt  of  slate,  there  is  a  band  of  conglomerate,  which  ap¬ 
pears  west  of  Hell  Hollow,  and  at  various  points  between  there  and 
Green  Gulch.  This  is  made  up  of  pebbles  of  a  slaty  rock,  with  many 
others  of  a  hard,  gray,  silicious  limestone. 

It  is  in  the  great  slate  belt  that  the  larger  part  of  the  very  numerous 
gold-bearing  quartz  veins  which  occur  on  the  estate  are  found.  Mr. 
King  examined  about  one  hundred  and  fifty  outcrops,  and  found  that, 
in  much  the  larger  number  of  cases,  the  veins  coincide  in  dip  and  strike 
with  the  rock  in  which  they  are  inclosed ;  although,  in  a  few  instances, 
they  appear  to  cut  the  slates  at  a  slight  angle.  Nearly  all  the  veins 
which  occur  in  the  granite,  and  they  are  quite  numerous,  have  the 
same  dip  and  strike  as  those  in  the  slates;  a  few,  however,  run  at 
right-angles  to  these.  Parallel  with  these  cross-veins,  in  the  granite, 
are  dykes  of  trap,  from  a  foot  to  fifteen  inches  in  width,  which  are  made 


*  For  the  particulars  of  this  discovery,  and  a  description  of  the  fossils,  with  figures, 
by  Mr.  Meek,  see  the  Appendix  to  this  volume.  The  geological  age  of  the  auriferous 
slates  being  one  of  the  most  important  problems  to  he  solved  by  the  Survey,  and  every¬ 
thing  hearing  on  this  question  being  of  the  greatest  interest,  the  publication  of  the  descrip¬ 
tion  and  figures  of  these  fossils,  which  would  properly  come  in  the  second  volume  of  the 
palaeontological  portion  of  the  Report,  will  be  hastened  by  giving  them  in  this. 


THE  WESTERN  SLOPE - MARIPOSA  COUNTY. 


227 


up  of  a  uniformly  tine-grained  and  compact  material,  destitute  of  pris¬ 
matic  or  jointed  structure. 

The  granite  is  a  finely-crystalline  variety,  in  which  both  hornblende 
and  mica  are  present.  The  outcrops  are  smooth  and  rounded,  and 
exhibit  evidence  of  the  concentric  structure  so  often  observed  in  this 
rock,  and  which  is  developed  as  it  undergoes  decomposition  by  weath¬ 
ering.  The  region  along  the  junction  of  the  granite  and  slates  is  covered 
with  a  thick  accumulation  of  disintegrated  granitic  detritus  and  gravel, 
which  prevented  a  careful  examination  of  the  junction  of  the  two  for¬ 
mations. 

For  a  detailed  account  of  the  workings  on  the  various  quartz  veins 
of  this  estate,  reference  is  made  to  the  volume  devoted  to  Economical 
Geology,  Mining  and  Metallurgy.*  A  few  facts  may  be  stated  here  to 
give  an  idea  of  the  magnitude  and  importance  of  these  veins. 

The  Pine  Tree  and  Josephine  Mines  are  on  the  northwestern  end  of 
the  Mount  Bullion  Iiidge,  about  a  mile  and  a  half  from  the  Merced 
River.  These  mines  are  in  what  might  be  called  with  truth  one  of  the 
most  extraordinary  masses  of  quartz  yet  discovered.  The  average 
thickness  is  fully  twelve  feet,  and  in  places  it  expands  to  forty  feet,  all 
of  solid  veinstone.  The  mass  has  been  opened  and  worked,  chiefly  at 
an  elevation  of  about  1300  feet  above  the  river,  by  levels  run  in  at  four 
different  elevations.  Portions  only  of  this  vein  contain  gold  enough  to 
pay  for  working,  and  the  best  of  the  lode  is  not  very  rich.  The  aver¬ 
age  yield  of  the  Pine  Tree  quartz  worked  in  the  mill  was  considered 
to  be  $12  per  ton  in  1860 ;  but  the  quality  of  the  ore  has  deteriorated 
since  that  time.  The  processes  at  the  Benton  Mill*  where  this  quartz 
was  worked,  were  so  defective,  that  it  was  evident  that  a  very  large  por¬ 
tion  of  the  gold  was  lost. 

The  Josephine  Mine,  a  little  southwest  of  the  Pine  Tree,  is  on  an  enor¬ 
mous  outcrop  of  quartz,  averaging  twenty  feet  in  thickness,  and  from 


*  Whenever  reference  is  made  to  other  volumes,  which  are  expected  to  form  a  portion 
of  the  Final  Report  of  the  Geological  Survey  of  the  State  of  California,  the  reader  will 
please  understand  always,  that  the  publication  of  such  volumes  is  dependent  on  the  caprice 
of  a  future  Legislature ;  and  that,  of  course,  no  positive  engagement  is  made  that  they 
will  ever  appear.  It  is  only  meant  to  be  understood  that  they  will  form  a  part  of  the 

9 

series  of  our  publications,  provided  our  plans  are  not  interfered  with. 


228 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


which  many  thousand  tons  of  rock,  with  a  small  percentage  of  gold, 
have  been  taken.  The  appearance  of  this  mine,  in  1860,  was  most  re¬ 
markable  on  account  of  the  immense  cavities  left  in  the  quartz  entirely 
unsupported,  and  which  have  probably  caved  in  before  this  time. 

The  quartz  from  the  Pine  Tree  Mine  was  crushed,  together  with  that 
from  the  Josephine,  at  the  Benton  Mill,  a  sixty-four  stamp  mill,  moved 
by  the  water  of  the  Merced.  The  average  yield  of  the  rock  worked 
at  this  mill  was,  in  1861,  $8.98  per  ton.  The  total  cost  of  extracting 
the  quartz,  conveying  it  to  the  mill,  and  of  crushing  and  amalgamating 
was  $4.57  per  ton,  leaving  a  handsome  profit.  The  actual  percentage 
of  gold  in  the  rock  crushed  was  certainly  a  good  deal  higher  than  this, 
as  an  examination  of  the  tailings  showed  most  distinctly.  The  mill 
was  in  every  way  unfortunate,  both  in  its  location  and  construction. 
It  yet  remains  to  be  shown  whether  by  a  system  of  judicious  changes 
at  the  mill,  combined  with  careful  selection  of  the  quartz  and  skill  in 
following  the  richer  shoots,  the  Josephine  and  Pine  Tree  Mines  can  be 
worked  with  profit,  which  at  present  is  not  the  case,  as  there  has  been 
a  considerable  falling  oft*  of  the  yield  of  the  quartz  extracted  since  1860. 
A  portion  of  the  Benton  Mill  has  been  reconstructed,  with  improve¬ 
ments,  since  the  present  company  took  possession  of  the  estate ;  but 
of  the  result  we  are  not  informed. 

It  has  never  been  shown  by  the  workings,  whether  the  Josephine 
and  Pine  Tree  masses  of  quartz  are  connected  with  each  other,  or 
whether  they  unite  to  the  south.  Various  excavations  have  been  made 
in  the  general  direction  of  the  supposed  continuation  of  the  united 
veins,  and  some  rich  quartz  found ;  but  not  enough,  continuously,  to 
pay  expenses. 

There  is  another  group  of  veins  six  miles  southeast  of  the  Josephine, 
which  occupy  a  space  about  three  miles  in  length,  and  which,  if  not 
absolutely  continuous,  are  at  least  closely  connected  with  each  other. 
Of  the  outcrops  in  this  group,  that  known  as  the  Princeton  Vein  is  the 
most  important,  and  the  mine  of  that  name  has  been  in  former  times 
one  of  the  most  productive  in  California ;  it  is  also  one  of  the  deepest 
and  most  extensive  in  its  workings,  having  been  opened  for  a  length  of 
1400  feet,  and  to  a  depth  of  over  500.  Its  direction  is  nearly  that  of 
the  inclosing  strata,  but  with  many  flexures,  the  courses  in  the  same 


THE  WESTERN  SLOTE  —  MARIPOSA  COUNTY. 


229 


level  sometimes  making  as  great  an  angle  with  each  other  as  30°. 
The  dip,  which  is  always  to  the  east,  or  with  the  formation,  varies  con¬ 
siderably  ;  at  the  surface,  in  the  western  shaft,  it  was  64° ;  at  a  depth 
of  one  hundred  feet,  57°.  In  the  Ridgway  Shaft,  it  was  from  48°  to 
50°.  The  thickness  of  the  lode  varied  from  a  few  inches  to  eight  feet. 


The  rock  in  which  this  vein  is  inclosed  is  a  dark-colored,  fine-grained, 
and  rather  soft  argillaceous  shale,  which  material  also  often  forms  fine 
layers  in  the  veinstone  itself.  This  latter  is  quite  different  in  its  appear¬ 
ance  from  the  veinstone  of  the  Pine  Tree  and  Josephine,  containing 
more  pyrites,  blende  and  galena,  and  less  blue  carbonate  of  copper, 
besides  showing  free  gold  in  many  places,  so  as  to  form  beautiful  speci¬ 
mens,  some  of  which  are  almost  unsurpassed  in  beauty.  The  average 
yield  of  the  quartz  from  the  Princeton  Vein,  in  1860,  was  from  $25  to 
$31,  according  to  the  mill  in  which  it  was  worked.  It  is  said  that 
nearly  $2,000,000  have  been  taken  from  this  mine;  and  it  is  also  under¬ 
stood  that  at  the  present  depth  the  yield  of  the  quartz  in  gold  has  fallen 
off*  very  materially,  which  is  one  of  the  prominent  causes  of  the  failure 
of  the  company  now,  or  at  least  recently,  in  possession  of  this  estate, 
to  make  their  operations  profitable. 

The  Mount  Opliir  vein  is  at  the  northwestern  end  of  the  group  to 
which  the  Princeton  belongs.  It  has  not  yet  been  very  extensively  or 


successfully  worked. 

Another  group  of  veins  is  that  near  the  village  of  Mariposa,  where 
the  first  quartz  mining  on  the  estate,  and,  as  is  supposed,  the  earliest 
in  California,  was  done.  The  principal  vein  is  the  Mariposa,  which  lias 
been  traced  on  the  surface  for  about  two  miles,  a  little  to  the  northeast 
of  the  village  of  the  same  name.  This  lode  has  proved  to  contain 
several  very  rich  “  pockets,”  and  since  the  giving  out  of  the  Princeton 
Mine,  has  been  the  principal  hope  and  resource  of  the  Company. 

There  are  many  other  outcrops  of  auriferous  quartz  on  the  Mariposa 
estate,  and  a  great  deal  of  “  prospecting”  has  been  done  by  the  Com¬ 
pany.  High  expectations  have  been  excited  by  this  property,  and  not 
without  reason ;  its  development  has,  thus  far,  however,  been  anything 
but  satisfactory.  The  causes  of  this  ill-fortune  may  be  examined  in 
the  volume  of  Economical  Geology,  where  full  details  will  be  found  of 
the  working  of  the  mills  and  mines,  if  those  who  may  be  in  charge  at 


230  GEOLOGY  OF  THE  SIERRA  NEVADA. 

the  time  of  publication  of  that  part  of  the  Report  permit  the  neces¬ 
sary  examinations  and  experiments  to  be  made,  and  the  results  given 
to  the  public. 

A  large  amount  of  placer  mining  has  been  done  in  other  portions  of 
Mariposa  County,  and  many  quartz  veins  worked,  not  often,  however, 
on  a  large  scale.  In  1863  there  was  considerable  excitement  in  regard 
to  the  region  of  the  South  Fork  of  the  Merced  River,  and  rich  speci¬ 
mens  were  shown  as  having  come  from  that  district. 

There  are  heavy  outcrops  of  quartz  near  Coulterville,  which  are 
supposed  by  some  to  be  the  continuation  of  the  great  quartz  vein  of 
the  Pine  Tree  and  Josephine.  If  it  cannot  be  proved  to  be  positively 
the  same  vein,  it  is  certain  that  there  is  a  series  of  enormously  heavy 
outcrops  of  quartz,  which  run  nearly  in  a  straight  line,  beginning  at 
the  Mariposa  estate,  and  continuing  as  far  as  Jackson  in  Amador 
County,  a  distance  of  about  70  miles.  It  is  also  certain  that  the  prin¬ 
cipal  quartz  mines  and  heaviest  placer  diggings  are  nearly  in  the  line 
of  this  series  of  outcrops,  at  least  in  the  counties  of  Mariposa,  Tuol¬ 
umne,  Calaveras,  and  Amador,  as  will  be  more  fully  noticed  farther 
on  in  this  chapter.  There  are  several  localities  near  Coulterville 
where  quartz  has  been  extracted ;  but  none  of  them  appear  to  have 
given  rise  to  permanent  and  valuable  mines;  at  least,  none  were  work¬ 
ing  in  that  vicinity  in  1863.  A  number  of  outcrops  were  examined, 
however,  and  some  of  them  appeared  to  offer  inducements  for  more 
careful  exploration  than  they  have  heretofore  received. 

There  is  an  interesting  quartz  lode  on  the  north  bank  of  the  Merced, 
near  Horseshoe  Bend,  on  a  steep  hill-side,  at  an  elevation  of  some  500 
feet  above  the  river.  The  vein  is  about  six  inches  wide,  as  seen  at  the 
surface,  runs  about  north  and  south,  and  dips  to  the  west  at  an  angle 
of  65°.  It  resembles  other  auriferous  quartz  veins  in  most  respects; 
but  also  carries  with  it,  on  its  foot-wall,  a  thin  seam  of  quartz  containing 
cinnabar,  in  crystalline  plates  and  bunches.  The  seam  is  about  an  inch 
wide,  and  appeared  to  be  continuous.  There  is  only  one  other  locality 
in  the  auriferous  slate  formation  where  this  ore  has  been  seen  by 
us  in  place,  and  it  is  a  very  interesting  occurrence,  although  there  is 
no  reason  to  suppose  that  the  vein  can  be  worked  with  profit  for  the 


TI1E  WESTERN  SLOPE - MARIPOSA  COUNTY. 


231 


quicksilver  it  contains.  The  rock  inclosing  this  vein  is  a  greenish, 
highly  metamorphic  slate. 

A  few  miles  northwest  of  Coulterville  there  is  a  fine  outcrop  of  the 
great  quartz  vein  of  California  in  the  Pehon  Blanco  (White  Rock), 
a  prominent  elevation,  of  which  the  crest  is  a  great  white  mass  of 
quartz,  visible  from  a  great  distance,  and  as  contrasting  with  the  deep 
green  of  the  chaparral  which  covers  the  sides  of  the  hill,  it  forms  a 
beautifully  picturesque  object.  A  quartz  mine  has  been  extensively 
worked  here,  and  is  understood  to  pay  a  very  handsome  profit.  It  is 
known  as  McAlpine’s  Lode.  The  workings  are  on  the  back  of  the 
great  quartz  lode  on  the  north  side  of  the  Pehon  Blanco.  Beneath  the 
productive  streak,  there  is  an  immense  mass  of  white  quartz^  entirely 
destitute  of  gold,  and  at  least  forty  feet  thick.  Above  it  there  is  also 
quartz,  but  of  a  very  different  character  from  that  below;  being  more 
ferruginous  and  mixed  with  metamorphic  slate.  The  great  mass  of 
quartz  which  underlies  the  lode  has  been  laid  bare  by  stripping,  over 
a  length  of  a  hundred,  and  a  height  of  forty  feet,  and  its  smooth  and 
regularly-curved  surface  is  an  interesting  object  to  the  eye  of  the  geolo¬ 
gist.  The  productive  lode  has  been  opened  for  a  length  of  1300  feet ; 
and,  in  places,  the  workings  have  reached  a  depth  of  300  feet,  where 
the  vein  is  more  nearly  vertical  and  quite  regular.  These  were,  in 
1863,  the  only  workings  on  the  great  quartz  vein  between  Coulterville 
and  Big  Oak  Flat. 

From  Coulterville,  the  most  frequented  trail.leads  to  the  Yosemite ; 
but,  as  this  valley  is  entirely  beyond  the  mining  region,  it  will  be  de¬ 
scribed  in  the  chapter  relating  to  the  High  Sierra. 

Mariposa  County  differs  from  most  of  the  mining  region  of  Califor¬ 
nia,  in  that  it  has  very  little  of  the  volcanic  accumulations  upon  its 
surface  wdiich  are  elsewhere  so  extensively  developed.  Hence  there  . 
are  no  great  hydraulic  washings,  and  the  placer  mines  having  very 
much  diminished  in  yield,  the  county  must  look  to  the  development 
of  its  quartz  lodes  for  the  largest  future  advance  in  its  prosperity. 


232 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


Section  IV. — Tuolumne  County. 

Tuolumne  County  is  one  of  the  most  interesting  regions  in  the  State, 
especially  on  account  of  the  large  development  of  Tertiary,  Post-Ter¬ 
tiary  and  volcanic  materials  which  overlie  the  older  slates,  and  which 
are  mined  extensively  in  tunnel  and  hydraulic  washings;  these  are 
particularly  remarkable  as  containing  more  of  the  remains  of  large 
animals,  such  as  the  mastodon  and  elephant,  than  the  same  formations 
in  any  other  portions  of  California.  . 

Tuolumne  County  is  intersected  longitudinally  by  the  river  of  that 
name,  and  has  for  its  southern  limit  the  divide  between  that  river  and 
the  Merced;  its  northern  boundary  is  the  Stanislaus.  Its  shape  ap¬ 
proaches  that  of  a  rectangle,  and  it  is  about  sixty  miles  long  from  north¬ 
east  to  southwest,  and  forty  in  the  opposite  direction.  The  southwest¬ 
ern  part  of  the  county  is  pretty  thickly  inhabited,  while  the  higher 
portion  is  almost  as  much  a  terra  incognita  as  it  was  in  1849.  A  single 
road  crosses  the  mountains,  from  Sonora  to  Aurora  and  Mono  Lake  ; 
but  south  of  that,  as  far  as  the  Yosemite  trail  to  Mono,  all  is  unex¬ 
plored.  Our  party  passed  over  the  Sonora  trail,  and  such  observations 
as  were  made  in  the  High  Sierra,  within  the  limits  of  this  county,  will 
be  found  in  the  succeeding  chapter. 

The  auriferous  slate  formation  occupies  a  belt  of  about  twenty-five 
miles  in  width,  in  the  lower  part  of  this  county ;  all  the  remainder  is 
underlaid  by  granite;  but  extensive  deposits  of  volcanic  materials  cover 
both  slates  and  granite,  in  many  places,  and  over  a  considerable  area 
of  surface.  The  rocks  of  the  auriferous  series  exhibit  themselves  in 
Tuolumne,  as  elsewhere  in  the  lower  part  of  the  Sierra,  with  a  great 
variety  of  lithological  characters.  The  predominating  formations  are 
slates,  which  are  argillaceous  and  silicious,  rather  than  talcose.  Besides 
the  slates,  there  are  sandstones  in  various  stages  of  alteration  ;  but  they 
have  almost  everywhere  been  highly  metamorphosed  since  their  depo¬ 
sition.  They  frequently  pass  into  dioritic  or  trappean  varieties,  which 
it  is  difficult  to  distinguish  from  the  really  intrusive  or  eruptive  masses. 
They  also  assume  a  porphyritic  structure,  appearing  in  various  forms  * 
of  hornblende-porphyry,  and  passing  into  compact  hornblende-rock,  or 


THE  WESTERN  SLOPE 


TUOLUMNE  COUNTY. 


O  o  o 

£65 


amphibolite.  Serpentine  is  also  oue  of  the  forms  of  metamorphism  of 
the  rocks  of  the  auriferous  slate  series,  and  it  occurs  in  large  masses  in 
Tuolumne,  as  well  as  all  the  other  mining  counties.  Of  the  exact  dis¬ 
tribution  of  all  the  different  varieties  of  the  metamorphic  slate  and 
sandstone  series,  it  would  he  impossible  to  give  any  idea  without  an 
accurate  map,  and  of  the  larger  part  of  Tuolumne  County  there  is  no 
map  which  is  even  approximately  correct.  Besides,  our  investigations 
in  this  region  are  far  from  having  been  detailed  enough  to  enable  us  to 
lay  down  the  boundaries  of  the  different  subdivisions  of  the  auriferous 
formations.  A  small  party  is  now  in  the  field,  in  this  very  region, 
making  a  beginning  of  this  detailed  work,  which  will  be  continued  to¬ 
wards  the  north,  as  fast  as  it  can  he  done  with  accuracy. 

The  finely-laminated  slates,  which  appear  to  constitute  that  portion 
of  the  formation  in  which  the  auriferous  veins  are  best  developed,  ap¬ 
parently  occur  in  the  heaviest  masses  through  the  centre  of  the  mining 
region  of  the  county ;  these  may  be  traced  from  near  Jacksonville, 
north  through  Chinese  Diggings  to  Jamestown,  where  they  pass  under 
Table  Mountain,  but  reappear  on  the  north  side,  in  the  gorge  of  Stan¬ 
islaus  River,  and  extend  towards  Angel’s,  the  formation  having  a  more 
nearly  north  and  south  trend  here  than  it  has  farther  north.  The 
hornblendic  series  of  rocks,  including  the  porphyries,  are  well  displayed 
in  a  line  to  the  south  of  this,  as  near  the  Crimea  House.  Interesting 
outcrops  of  hornblende-rock  are  also  seen  near  Texas  Flat,  above 
Abby’s  Ferry,  where  the  hornblende  occurs  in  very  largely  crystalline 
masses,  sometimes  free  from  associated  minerals,  but  occasionally  con¬ 
taining  black  mica,  and  crossed  by  small  feldspathic  veins.  Serpentine 
occurs  in  a  large  outcrop,  about  two  miles  from  Jacksonville,  on  the 
road  to  Big  Oak  Flat,  near  Goddard’s  Ferry,  at  Stevens’  Bar;  it  is  here 
associated  with  black,  argillaceous  shales.  Metamorphic  magnesian 
rocks  also  occur  to  the  south  of  the  principal  belt  of  slates,  and  serpen¬ 
tine  beds  are  included  with  these,  and  are  characterized  by  the  presence 
of  large  deposits,  or  intercalated  masses,  of  chromic  iron,  as  is  seen 
near  the  Crimea  House.  The  dip  of  the  series  of  metamorphic  slates 
seems  to  be  everywhere  to  the  east  and  northeast,  and  usually  at  a 
*  high  ail^le ;  the  larger  number  of  observations  are  between  60°  and  80°. 


GEOL.  VOL.  I. — 30 


234 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


Their  strike  is  also  variable,  although  on  the  average 

K.  30°  W. 


not  far  from 


Of  the  geological  age  of  the  auriferous  belt  in  Tuolumne,  we  have  but 
little  direct  evidence  other  than  that  of  its  connection  with  rocks  known 
to  be  of  Jurassic  age  to  the  south,  and  of  both  Triassic  and  Jurassic  to 
the  north.  A  single  fossil,  an  impression  on  a  dark-colored,  highly 
silicious  slate,  was  found  by  Mr.  Alfred  Frick,  in  situ ,  at  the  mouth  of 
Mormon  Creek,  between  Robinson’s  and  Knight’s  Ferries,  on  the  Stan¬ 
islaus,  and  by  him  presented  to  Mr.  Rdmond.  The  fossil,  although  not  in 
a  very  satisfactory  condition,  appears  to  be  identical  with  the  Goniatites 
Icevidorsatus ,  found  also  in  the  rocks  of  the  Humboldt  Range,  which  are 
known  to  be  of  Upper  Triassic  age.  If  not  this  species,  it  is  still  almost 
certainly  of  Triassic  age,  and  its  discovery  adds  one  to  the  already  quite 
numerous  links  in  the  chain  of  evidence  going  to  prove  that  the  aurif¬ 
erous  slates  do  not  belong  to  the  Palaeozoic  epoch. 

The  limestone  belt  included  in  the  Sierra  system  of  rocks  is  particu¬ 
larly  well  developed  in  Tuolumne  County,  and  its  surface  has  been  so 
extensively  washed  off  in  mining,  that  there  are  many  beautiful  expo¬ 
sures  of  it.  Owing  to  the  want  of  an  accurate  map,  it  is  impossible  to 
say  what  are  the  exact  relations  of  the  different  masses  of  limestone 
observed,  as  far  as  position  is  concerned;  this  question  will,  however, 
be  taken  up  farther  on.  At  all  points  visited,  this  rock  has  very  nearly 
the  same  lithological  characters,  being  usually  quite  crystalline  and 
sometimes  highly  so,  of  various  shades  of  bluish-gray,  passing  into 
white  where  most  metamorphosed,  and  often  showing  very  distinctly 
the  lines  of  bedding,  either  by  thin  micaceous  partings  or  darker  lines 
in  the  highly  altered  portions.  The  most  .careful  search  has  failed  to 
reveal  the  presence  of  even  a  trace  of  a  fossil  in  it  through  this  region, 
although  there  are  places  where  it  would  appear  that  metamorphism 
has  not  been  carried  far  enough  to  obliterate  entirely  the  impressions 
of  organic  remains  if  any  such  had  existed. 

The  most  southerly  point  in  the  county  where  this  belt  has  been  seen 
by  us  is  at  Bull  Creek,  on  the  Big  Oak  Flat  trail  to  the  Yosemite, 
about  six  miles  southeast  of  Bower  Cave,  the  trail  passing  over  it  for  a 
distance  of  two  miles.  The  rock  here  is  pretty  distinctly  stratified,  and 
less  metamorphic  than  usual ;  but  no  fossils  were  discovered. 


THE  WESTERN  SLOPE - TUOLUMNE  COUNTY. 


235 


At  Bower  Cave,  on  the  north  fork  of  the  Merced,  at  a  point  near 
where  the  Coulterville  and  Big  Oak  Flat  trails  to  the  Yosemite  come 
together,  and  said  to  be  twelve  miles  from  the  former  place,  the  lime¬ 
stone  is  well  displayed,  and  is  remarkable  as  containing  a  very  pictur¬ 
esque  and  quite  unique  cave,  the  peculiar  character  of  which  may  per¬ 
haps  he  understood  from  the  annexed  cross-section  (Fig.  34).  It  is  an 


Fig.  34. 


SECTION  OF  BOWER  CAVE. 


immense  crack  in  the  limestone,  open  to  the  air  at  the  surface,  and 
irregularly  widened  out  in  a  cave-like  manner  below,  by  the  action  of 
currents  of  water.  On  the  upper  side  of  the  obliquely-descending  cre¬ 
vice  an  overhanging  ledge  of  rock  permits  the  vertical  depth  of  the 
cave  to  the  level  of  the  water,  which  partly  fills  it,  to  be  measured ;  it 
is  109  feet.  The  length  of  the  open  crevice  is  133  feet,  and  its  width 
86.  At  various  heights  deep  cavities,  or  small  caves,  are  worn  in  the 
rock,  some  of  which  may  be  followed  for  a  considerable  distance.  The 
picturesque  effect  of  the  cave  is  greatly  heightened  by  the  growth 
within  it  of  three  large  maple  trees,  of  which  the  branches  project  out 
at  the  top.  The  water  at  the  bottom  is  exceedingly  pellucid,  and  per¬ 
mits  the  ramifications  of  the  crevice  beneath  its  surface  to  be  seen  for 
a  depth  of  at  least  forty  feet.  Access  can  be  had  to  the  bottom  of 
the  cave  by  series  of  ladders,  and  a  boat  is  provided  for  the  use  of  vis- 

v 

itors,  as  also  a  platform,  which  permits  of  a  comfortable  and  cool  stay 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


o  o  a 


in  this  curious  place,  which  seems  to  be  peculiarly  adapted  for  a  picnic 
in  hot  weather. 

The  limestone  next  makes  its  appearance,  towards  the  northwest, 
at  Kincaid  Flat,  about  three  miles  from  Sonora ;  it  has  not  been  traced 
or  proved  to  exist  continuously  over  the  region  between  there  and 
Bower  Cave.  From  Kincaid  Flat  to  Ahby’s  Ferry  it  occupies  a  broad 
belt  of  ground,  trending  about  K.  25°  to  30°  W.,  and  expanding  very 
much  in  width  just  at  Sonora,  but  contracting  again  rapidly  towards 
M  urphy’s.  The  distance  across  it,  at  right-angles  to  the  strike,  between 
Springfield  and  Yankee  Hill,  is  about  three  and  a  half  miles,  which  is 
a  considerably  greater  width  than  this  formation  has  been  observed 
to  have  at  any  other  place  in  the  State.  Between  Kincaid  Flat  and 
Abby’s  Ferry  nearly  the  whole  surface  of  this  rock  has  been  washed 
clean  of  the  superincumbent  detritus,  and  exhibits  a  singularly  curious 
appearance.  It  is  worn  into  deep  cavities,  which  are  very  irregular, 
but  which  have  their  greatest  length  in  the  direction  of  the  stratifica¬ 
tion,  and  also  coincide  in  their  dip  with  that  of  the  beds  of  rock  be¬ 
tween  which  they  occur.  These  cavities  extend  down  sometimes  as 
much  as  fifty  feet  below  the  surface ;  but,  in  general,  their  depth  is 
from  ten  to  twenty  feet.  The  edges  of  the  ridges  between  the  depres¬ 
sions  have  a  rounded  and  corroded  look,  showing  that  they  have  been 
gradually  worn  away  by  the  action  of  currents  of  water,  and  not 


Fig.  35. 


LIMESTONE  AND  TRAP  DYKE  NEAR  SONORA. 
a.  Superficial  detritus,  b.  Trap  dyke.  c.  Limestone. 


scooped  out  by  the  passage  of  gravel  and  detritus.  The  wood-cut  (Fig. 
35)  will  illustrate  this  peculiar  surface  of  the  limestone,  as  well  as  an- 


THE  WESTERN  SLOPE - TUOLUMNE  COUNTY. 


other  feature  which  characterizes  this  belt  of  rock,  namely,  that  it  is 
intersected  by  numerous  dykes  of  trap;  these  run  almost  always  about 
at  right-angles  to  the  strike  of  the  formation,  stand  nearly  vertical,  and 
are  often  many  feet  in  thickness.  In  some  parts  of  the  belt  of  lime¬ 
stones  these  dykes  are  surprisingly  numerous,  as,  for  instance,  near 
Abby’s  Ferry.  They  appear  to  be  almost  entirely  confined  to  the  lime¬ 
stone  formation,  and  not  to  extend  into  the  slates  which  lie  next  to  it, 
a  very  curious  circumstance,  if  farther  investigations  should  prove  it  to 
be  everywhere  true.  This  limestone  is  quite  extensively  quarried  a 
little  northwest  of  Columbia,  where  a  good  material  for  gravestones, 
monuments,  and  architectural  purposes,  is  readily  obtained  in  large 
blocks. 

In  some  localities  the  limestone  disintegrates  readily,  and  crumbles 
into  a  powder,  which  on  examination  is  seen  to  be  made  up  of  small 
crystals.  Beds  and  nodules  of  chert  are  observed  in  this  rock,  although 
not  frequently.  Metalliferous  ores  are  very  rarely  seen  in  it;  galena  is 
almost  the  only  one  found  in  the  limestone  about  Sonora,  and  that  only 
in  irregular  masses,  and  in  too  small  quantity  to  be  worth  working. 

Through  Tuolumne  County  the  north  edge  of  the  great  limestone 
belt  nearly  marks  the  line  between  the  metamorpliic  and  granitic 
rocks.  The  limestone  appears  to  pass  into  a  quartzose  slate,  by  taking 
into  its  composition  more  and  more  silica,  and  a  belt  of  this  rock,  pass¬ 
ing  occasionally  into  gneiss,  occupies  in  some  places  a  considerable 
area  between  the  limestone  and  the  granite. 

Quartz  mining  has  been  carried  on  at  many  points  in  Tuolumne 
County,  although  most  of  the  valuable  veins  in  this  region  are  worked 
in  the  granite  and  not  in  the  metamorpliic  slates.  A  very  heavy  quartz 
vein  passes  a  little  south  of  Big  Oak  Flat,  cutting  the  strata  of  slate  in 
which  it  is  contained  at  a  small  angle,  the  lines  of  bedding  of  the  wall- 
rock  appearing  to  run  nearly  northwest  and  southeast,  while  the  vein 
of  quartz  has  a  strike  of  N.  30°  W. ;  it  dips  to  the  east  at  an  angle  of 
30°,  the  slates  themselves  standing  nearly  vertical.  This  is,  perhaps, 
the  most  marked  instance,  hitherto  observed  in  the  State,  of  a  heavy 
quartz  vein  differing  essentially  both  in  dip  and  strike  from  the  in¬ 
closing  rocks.  There  has  been  considerable  mining  done  at  this  point; 
but  it  seemed,  in  1863,  to  have  been  stopped,  by  the  burning  of  the 


238 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


mill.  There  are  other  localities  in  this  vicinity  where  quartz  mining 
has  been  carried  on,  or  where  preparations  were  making  at  the  time  of 
our  visit  to  begin  work,  the  number  of  veins  which  contain  some  gold 
being  quite  considerable. 

According  to  Mr.  Ashburner’s  notes,  there  were  in  operation  in 
Tuolumne  County,  in  1859,  thirty  quartz  mills,  which  had  cost  over 
$200,000  to  erect ;  but  not  more  than  half  of  these  were  in  existence 
in  1861.  The  scene  of  the  greatest  mining  activity  in  this  county  was, 
at  that  time,  near  Soulsbyville,  about  eight  miles  southeast  from  Sonora. 
At  this  place  there  were  three  mills,  two  of  which  were  running  on 
quartz  from  the  Soulsby  vein,  and  the  other  on  custom-work. 

The  Soulsby  vein  is  inclosed  in  granite,  and  stands  nearly  vertical ; 
it  has  a  strike  of  almost  exactly  north  and  south,  magnetic.  Its  ave¬ 
rage  width  is  about  one  foot,  the  widest  place  in  it  being  four  feet  six 
inches.  The  granite  which  forms  the  wall-rock  is  exceedingly  hard 
and  compact,  and  the  vein  perfectly  well-defined,  and  very  rich  in  the 
sulpliurets  of  iron,  lead,  copper,  and  zinc, — the  two  former,  however, 
in  much  the  largest  proportion,  blear  the  surface,  where  the  sul- 
phurets  were  decomposed,  the  veinstone  was  worked  with  great  profit; 
its  average  yield,  in  1861,  was  $50  per  ton,  although  some  of  it  has 
produced  six  or  seven  times  as  much. 

Two  mines  were  worked  on  this  vein,  one  called  the  Soulsby,  and 
the  other  the  Platt  Mine ;  each  of  these  had  a  mill,  the  first  one  of 
twenty  stamps ;  the  other  one  of  ten.  The  Gilson  Mill,  a  few  rods 
south  of  the  Platt  Mill,  was  built  to  run  on  rock  from  another  claim  on 
the  same  vein ;  this  was  also  a  ten-stamp  mill,  and  was  running,  in 
1861,  on  rock  from  the  Draper  vein.  This  vein  is  one  and  a  half  miles 
from  Soulsby’s,  and  is  also  inclosed  in  granite,  and  very  nearly  of  the 
same  character  as  the  Soulsby  vein.  At  Lomberdo’s  Mill,  two  miles 
east  of  Soulsby’s,  there  are  several  veins  in  the  granite,  nearly  parallel 
with  each  other,  and  running  about  north  and  south.  Of  these,  the 
only  one  worked,  in  1861,  was  the  “  Louisiana  claim,”  the  quartz  from 
which  yielded  about  $20  per  ton. 

There  is  a  group  of  quartz  mines  and  mills  about  3J  miles  from 
Soulsby’s,  which  were,  in  1861,  of  considerable  importance.  Of  these, 
the  Eureka  Mine  was  worked  on  a  vein  in  the  slates  close  to  their  June- 


TIIE  WESTERN  SLOTE  —  TUOLUMNE  COUNTY. 


239 


tion  with  the  granite,  bearing  about  N.  25°  W.,  and  dipping  east  at 
an  angle  of  50°.  The  mill  has  twenty  stamps,  and  is  run  by  a  water¬ 
wheel  fifty-five  feet  in  diameter.  The  yield  of  the  quartz  was  estimated 
at  $12  per  ton.  Sower’s  Mill,  near  the  Eureka,  was  run  on  rock  from 
a  vein  said  to  be  a  continuation  of  the  one  worked  for  that  mill;  it  was 
doing  but  little  in  1861. 

The  Confidence  Mill  is  about  four  miles  northeast  of  Soulsby’s,  has 
ten  stamps,  and  was  run  on  rock  from  a  vein  in  the  granite,  distant 
about  a  quarter  of  a  mile  to  the  east.  The  quartz  is  very  hard  and 
yielded  from  $10  to  $20  per  ton ;  its  width  was  from  three  to  twelve 
feet. 

The  Telegraph  Mill,  on  the  south  fork  of  the  Stanislaus,  and  about 
thirteen  miles  from  Sonora,  was  run  on  a  vein  inclosed  in  a  belt  or 
slates,  which  occurs  here  isolated  from  the  main  body  of  the  auriferous 
slate  formation.  The  vein  has  the  usual  course  and  dip  of  the  inclos¬ 
ing  rock,  running  N.  25°  W.,  and  dipping  east  at  an  angle  of  50°.  Its 
width  is  from  a  few  inches  to  twelve  feet*  and  it  yielded  from  $15  to 
$47  per  ton,  the  average  of  one  thousand  tons  stamped  between  Sep¬ 
tember  10th,  1860,  and  May  29th,  1861,  being  $30.80  per  ton. 

At  Tuttletown,  five  miles  west  of  Sonora,  there  were,  in  1861,  sev¬ 
eral  quartz  mills,  of  which  only  two  were  in  operation ;  these  were 
Street  &  Co.’s,  and  Patterson  &  Co.’s,  both  doing  a  small  business,  on 
quartz  of  a  rather  low  grade  of  richness. 

The  great  vein  of  Mariposa  and  the  Penon  Blanco  appears  to  crop 
out  in  Tuolumne  County  about  a  mile  below  Jamestown,  where  there 
is  a  large  mass  of  quartz*  which  can  be  seen  from  a  long  distance  to 
the  east.  It  forms  several  eminences,  known  by  the  names  of  Whiskey 
Hill,  Poverty  Hill,  Quartz  Hill,  and  other  equally  picturesque  appella¬ 
tions.  The  main  vein  is  very  irregular  in  width,  varying  from  two  feet 
to  several  rods,  and  has  been  repeatedly  worked  for  gold,  but  never 
found  sufficiently  rich  to  pay  expenses*  Near  the  large  vein,  and  nearly 
parallel  with  it,  are  several  smaller  ones,  which  have  been  profitably 
mined.  In  1861,  one  of  the  best  mines  in  this  vicinity  was  that  of 
Knox  &  Co.,  on  a  vein  about  two  hundred  feet  east  of  the  main  one. 
This  averaged  about  one  foot  in  width,  went  down  perpendicular  for 
the  first  thirty  feet,  and  then  dipped  to  the  east  at  an  angle  of  70°. 


240 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


The  foot-wall  also  contains  gold,  in  a  “  casing”  of  soft  slate,  from  six 
to  ten  inches  thick,  and  often  very  rich.  The  average  yield  of  the 
quartz  from  this  vein  was  given  at  $20  per  ton.  The  mill  of  Ivnox  & 
Co.  was  a  small  one  of  only  five  stamps.  The  Italian’s  Mill,  of  two 
stamps,  was  run  on  quartz  from  the  same  vein  as  that  of  Knox  &  Co. 
The  Yaney  Mill,  on  Wood’s  Creek,  below  Jamestown,  of  six  stamps, 
was  run  on  custom-work,  in  1861.  Judge  Preston’s  mill,  a  little  below 
the  last  mentioned,  having  eight  stamps,  was  running  on  quartz  from 
a  vein  in  Quartz  Mountain,  parallel  with  the  great  vein,  and  twenty  or 
twenty-five  feet  to  the  east  of  it ;  it  was  about  eighteen  inches  wide  ; 
its  yield  was  not  known.  Snyder’s  Mill,  on  Wood’s  Creek,  has  three 
stamps,  and  was  run  on  quartz  from  a  vein  on  Whiskey  Hill,  which 
had  paid  well  for  several  years  previous  to  1861. 

IIow  many  of  all  these  mills  have  been  moved  over  to  Washoe,  or 
have  otherwise  disappeared,  and  how  many  new  ones  have  been  built, 
since  1861,  we  have  no  means,  at  present,  of  stating. 

A  new  district  was  opened  on  Sugar  Pine  Creek,  about  twelve  miles 
northeast  of  Sonora,  in  1861,  which,  when  visited  in  1863,  was  found 
to  have  some  very  promising  mines,  and  one  which  was  celebrated 
over  all  this  part  of  the  State  for  its  richness.  This  was  the  Excelsior 
Mine,  owned  by  Gilliss,  Holton  &  Gilmore,  who  commenced  operations 
in  December,  1861.  The  house  is  at  an  elevation  of  4350  feet  above 
the  sea.  The  vein  is  inclosed  in  granite,  which  is  the  only  rock  seen  in 
the  region.  In  the  summer  of  1863,  the  vein  had  been  opened  to  a 
depth  of  two  hundred  feet,  by  a  shaft  sunk  on  the  lode;  its  inclination 
was  found  to  be  to  the  northeast,  at  an  angle  of  40°  near  the  surface, 
and  27°  at  the  bottom.  The  vein  runs  about  K.  40°  E.,  and  averages 
nearly  two  feet  in  width.  The  casings,  or  selvages  of  the  vein,  on 
each  side  are  rich  in  gold,  and  if  the  veinstone  entirely  disappears,  pro¬ 
vided  there  is  any  seam  visible  in  the  rock,  it  is  sure  to  be  accompanied 
by  gold  on  each  side.  The  quartz  was  said  to  average  from  $50  to  $75 
a  ton,  and  some  had  paid  as  high  as  $250.  It  was  worked  in  a  ten- 
stamp  mill,  situated  on  the  Tuolumne  Kiver,  which  affords  abundant 
water  power,  the  rock  being  hauled  over  the  ridge  between  the  mine 
and  the  mill  by  steam  power,  and  descending,  on  the  other  side,  by 


THE  WESTERN  SLOPE - TUOLUMNE  COUNTY. 


241 


gravity,  on  an  inclined  plane,  to  the  valley  of  the  river,  which  here 
forms  a  gorge  over  1200  feet  in  depth. 

A  number  of  other  well-defined  veins  have  been  discovered  in  this 
vicinity,  but  few  of  them  had  been  worked  up  to  1863.  The  Pirate 
Mill,  built  in  1862,  is  on  the  Tuolumne  River,  four  miles  by  the  river, 
and  one  in  a  straight  line,  from  the  Excelsior.  It  has  ten  stamps,  but 
was  not  running  in  1863.  It  is  only  three  or  four  miles  from  this,  in  a 
southwesterly  direction,  to  the  Confidence  Mill,  already  noticed. 

In  this  county,  as  in  others  in  California,  the  quartz-mining  interest 
varies  in  aspect  from  year  to  year ;  and  to  keep  the  run  of  it  accurately 
would  require  that  the  whole  State  should  be  gone  over  annually.  It 
may  perhaps  be  convenient  in  another  part  of  this  Report  to  make 
some  general  remarks  on  this  branch  of  the  mining  business ;  but  it 
will  not  be  until  the  publication  of  the  volumes  on  Economical  Geology 
that  the  subject  will  be  thoroughly  discussed. 

As  before  mentioned,  the  detrital  and  volcanic  deposits  which  rest 
upon  the  granitic  and  auriferous  slate  formations,  in  this  county,  are  of 
great  interest,  for  it  is  in  this  region  that  these  deposits  have  yielded  a 
larger  number  of  fossils  than  have  been  found  in  any  other  part  of  the 
State  in  a  similar  position.  ■  These  detrital  strata  may  be  divided  into 
two  classes,  namely:  first,  such  as  rest  directly  on  the  surface,  without 
being  covered  by  any  other  formations ;  and,  second,  those  which  are 
overlain  by  more  or  less  extensive  accumulations  of  volcanic  materials. 

The  first  of  these  classes  presents  the  ordinary  features  of  the  surface 
deposits  of  the  gold  region,  or  the  usual  placer-diggings,  so  widely  dis¬ 
tributed  over  the  State,  and  which,  to  avoid  repetition,  will  all  be  treated 
of  at  once,  in  a  section  devoted  to  the  Post-Tertiary.*  Some  peculiar 
features  of  these  deposits  in  Tuolumne  County,  may,  however,  be  men¬ 
tioned  here. 

The  surface  of  the  limestone  through  the  whole  region  from  Kincaid 
Flat  to  the  Stanislaus  has  been  one  of  the  most  productive  areas  of 
placer-mining  in  the  State.  Nearly  the  whole  of  this  district  has  been 

*  Either  in  the  systematic  review  of  the  geological  formations  of  the  State,  which  will 
be  given  in  another  volume  of  the  geological  part  of  this  Report,  or,  else,  in  the  volume 
of  Economical  Geology. 

GEOL.  VOL.  I. — 31 


# 


242 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


worked  over,  although  in  some  places  the  accumulations  of  detritus  are 
so  extensive  that  considerable  masses  yet  remain  to  he  washed.  The 
deep  crevices  in  the  limestone  seem  to  have  acted  as  gigantic  riffles  to 
retain  the  gold  when  the  country  was  swept  over  by  the  currents  which 
have  deposited  the  gravelly  and  volcanic  materials  with  which  they  are 
filled.  Where  the  bottoms  of  these  cavities  lie  very  low,  they  are 
worked  out  by  the  aid  of  water-power. 

Texas  Flat  is  an  interesting  locality,  where  a  vast  accumulation  of 
calcareous  tufa  has  formed  over  the  auriferous  gravel,  in  an  ancient 
gulch  which  once  emptied  into  the  Stanislaus  River,  when  at  a  much 
higher  level  than  it  now  has.  The  same  tufa  formation  occurs  exten- 

O 

sively  on  the  southern  bank  of  the  Stanislaus,  where  it  assumes  a  most 
picturesque  appearance,  sometimes  rising  in  cliffs  which  resemble 
coral-reefs,  and  inclosing  small  caverns  lined  with  stalactitic  forma¬ 
tions.  In  this  tufaceous  deposit  many  fragments  of  the  bones  and 
teeth  of  large  mammalia  have  been  found,  including  the  mastodon, 
elephant,  and  horse,  and  also  both  land  and  fresh-water  shells,  the  lat¬ 
ter  at  the  bottom  and  resting  on  the  amphibolite,  which  here  forms  the 
bed-rock. 

All  through  the  region  northwest  of  Columbia,  as  far  as  Abby’s 
Ferry,  the  remains  of  the  elephant  and  mastodon  have  been  found  in 
greater  abundance  than  anywhere  else  in  the  State,  unless  it  may  pos¬ 
sibly  be  at  Kincaid  Flat.  At  Gold  Springs,  a  mile  northwest  of 
Columbia,  there  is  a  copious  spring  of  clear  water  which  forms  a  large 
pool,  a  quite  exceptional  circumstance  in  the  auriferous  region,  and  it 
is  not  unlikely  that  this  spring  may  have  existed  in  former  times, 
during  the  period  of  the  mastodon,  and  that  it  may  have  attracted  to 
this  vicinity  the  large  animals  whose  remains  are  found  there  so  abun¬ 
dantly.  But  few  of  these  relics  can  now  be  obtained,  as  most  of  them 
crumble  to  pieces  on  exposure,  and  the  others  rarely  escape  the  careless 
handling  to  which  they  are  subjected,  either  from  curiosity  or  reckless¬ 
ness.  A  wagon-load  of  bones  is  said  to  have  been  destroyed  by  afire  in 
a  miner’s  cabin  burned  near  Gold  Springs  some  years  ago.  A  complete 
review  of  all  the  mammalian  remains  found  in  the  auriferous  detritus  of 
this,  as  well  as  other  portions  of  the  gold  region,  must  be  deferred  to 
a  future  volume  of  this  Report,  as  our  stock  of  material,  in  this  depart- 


THE  WESTERN  SLOPE - TUOLUMNE  COUNTY. 


243 


merit,  is  still  scanty ;  farther  investigations  will,  it  is  hoped,  enable  us 
to  add  materially  to  what  we  have  already  secured. 

One  of  the  most  striking  features  in  the  topography  and  geology  of 
Tuolumne  County  is  the  so-called  “  Table  Mountain,”  a  name  given, 
throughout  the  State,  to  the  flat  table-like  masses  of  basaltic  lava  which 
have  been  rendered  so  conspicuous  by  the  erosion  of  the  softer  strata 
on  each  side,  and  which  now  exist  as  elevated  ridges,  dominating  over 
the  surrounding  country,  and  remarkable  for  their  picturesque  beauty, 
but  still  more  so  on  account  of  the  important  deposits  of  auriferous  de¬ 
tritus  which  lie  beneath  them. 

The  Table  Mountain  of  Tuolumne  County  is  a  flow  of  lava  origina¬ 
ting  in  the  lofty  volcanic  region,  beyond  the  Big  Trees  of  Calaveras, 
which  will  be  described  in  the  chapter  on  the  High  Sierra ;  it  conies 
down  on  the  north  side  of  the  Stanislaus,  forming  a  nearly  continuous 
ridge,  elevated  more  than  2000  feet  above  the  river.  Just  below  Abby’s 
Ferry,  the  Stanislaus  has  broken  through  the  once  continuous  basaltic 
ridge,  which  has  been  irregularly  worn  away  for  some  distance  from 
the  river,  but  which  reappears  as  a  continuous  mountain  a  little  south¬ 
west  of  Columbia,  and  continues  on  the  south  side  of  the  river,  form¬ 
ing  a  conspicuous  feature  of  the  scenery  as  far  as  Knight’s  Ferry,  a 
distance  of  about  twenty  miles  frorp  the  point  where  it  crosses  the 
river  and  enters  Tuolumne  County.  As  seen  from  a  distance,  this 
Table  Mountain  reveals  its  origin  at  once  in  the  contrast  between  the 
long  straight  line  of  its  upper  edge,  and  the  broken  and  curving  ones 
which  the  eroded  hills  of  the  auriferous  slates  everywhere  exhibit.  Its 
dark  color  and  the  comparative  absence  of  trees  or  shrubs  on  its  top  and 
sides,  also  indicate  very  clearly  that  the  material  of  which  it  is  com¬ 
posed  is  very  different  from  that  of  the  surrounding  hills.  The  annexed 
sketch  (Fig.  36),  taken  from  a  point  on  the  south  side  of  the  Tuolumne, 
and  at  a  distance  of  about  twelve  miles  in  a  southeasterly  direction 
from  the  nearest  point  of  Table  Mountain,  will  serve  to  show  some¬ 
thing  of  its  peculiar  character.  The  elevations  in  the  farthest  distance 
are  the  Bear  Mountain  Range,  near  Copperopolis. 

On  approaching  Table  Mountain  and  examining  the  material  of  which 
it  is  composed,  and  the  position  which  it  occupies,  it  is  seen  at  once 
that  it  is  a  vast  lava  flow,  of  which  the  upper  surface  remains  very 


244 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


nearly  at  the  level  and  with  the  form  which  it  originally  had  at  the 
time  of  its  consolidation,  while  its  edges  and  the  surrounding  country 


Fig.  36. 


DISTANT  VIEW  OE  TABLE  MOUNTAIN. 


have  been  denuded  and  washed  away,  so  that  the  topography  of  the 
region  is  entirely  different  from  what  it  once  was ;  in  fact,  it  is  almost 
the  reverse  of  it.  No  one  can  den^that  a  stream  of  melted  lava,  running 
for  forty  miles  down  the  slope  of  the  Sierra,  must  have  sought  and 
found  a  depression  or  valley  in  which  to  flow,  for  it  is  impossible  that  it 
should  have  maintained,  for  any  distance,  a  position  on  the  crest  of  a 
ridge.  Nor  could  the  valley  of  the  Stanislaus,  now  two  thousand  feet 
deep,  have  existed  at  that  time,  for  this  flow  of  lava  is  clearly  seen  to 
have  crossed  it  at  Abby’s  Ferry.  The  whole  face  of  the  country  must, 
therefore,  have  undergone  an  entire  change  since  the  eruption  took 
place,  during  which  this  mass  of  lava  was  poured  out.  Directly  over 
the  gorge  in  which  the  Stanislaus  Diver  now  runs,  there  must  then 
have  been  a  range  of  mountains,  and  the  same  is  true  of  the  other  side, 
where  now  is  the  valley  of  Wood’s  Creek,  for  such  ranges  must  have 
existed  in  order  to  form  and  wall  in  the  valley  in  which  the  current  of 
lava  flowed.  There  has  been,  therefore,  an  amount  of  denudation, 
during  the  period  since  this  volcanic  mass  took  its  present  position,  of 
not  less  than  three  or  four  thousand  feet  of  perpendicular  depth.  And 


THE  WESTERN  SLOPE - TUOLUMNE  COUNTY. 


245 


yet  this  was  all  done  during  the  most  recent  geological  epoch,  as  will  he 
seen  farther  on,  and  it  will  also  be  shown  that  these  surprising  changes 
have  not  been  peculiar  to  this  region,  but  that  the  whole  slope  of  the 
Sierra  throughout  the  Gold  Region  has  been  the  scene  of  similar  vol¬ 
canic  overflows  and  subsequent  remodelling  of  the  surface  into  a  new 
system  of  reliefs  and  depressions. 

The  fact  that  the  lava  flow  of  Table  Mountain  took  place  in  a  pre¬ 
existing  valley  is  not  only  capable  of  being  demonstrated  on  general 
principles,  but  is  confirmed  by  what  has  been  shown,  by  numerous  ex¬ 
cavations  beneath  it,  to  be  the  character  of  the  formation  on  which  it 
rests.  As  the  real  nature  of  the  deposits  covered  by  the  lava  is  not 
exhibited  on  the  surface,  a  long  time  would  probably  have  elapsed  be¬ 
fore  their  character  would  have  been  understood,  if  chance  had  not 
led  to  their  being  extensively  laid  open  by  mining  operations.  In  1854, 
a  party  of  miners,  in  cleaning  out  an  old  shaft,  near  Shaw’s  Flat, 
struck  a  rich  deposit  of  gravel,  evidently  of  a  different  character  from 
any  which  had  been  previously  discovered  in  this  region.  It  was  a 
part  of  the  old  river-bed,  now  mostly  covered  to  a  depth  of  several  hun¬ 
dred  feet,  but  there  near  the  surface,  either  because  the  overlying  vol¬ 
canic  and  detrital  beds  had  been  more  thoroughly  denuded  at  that 
point,  or  else  on  account  of  there  never  having  been  so  heavy  a  deposit 
of  them  in  that  particular  locality,  a  question  which  could  not  be  de¬ 
cided  without  a  more  detailed  survey  and  exploration  than  it  was  in 
our  power  to  make.  At  all  events,  this  discovery  was  followed  up,  and 
soon  resulted  in  demonstrating  that  there  was  beneath  the  mountain  a 
channel  of  auriferous  gravel,  portions  of  which  were  exceedingly  rich, 
and  which  has  been  worked  since  that  time,  with  a  heavy  expenditure 
of  time  and  money,  and  often  with  large  profits.  The  examination  of 
several  of  these  tunnels,  as  well  as  of  the  exterior  of  the  mountain, 
shows  the  following  facts  in  regard  to  the  character  of  the  formation. 

The  summit  of  Table  Mountain  is  occupied  by  a  heavy  bed  of  basaltic 
lava,  of  a  very  dark  color  and  dense  texture.  It  is  occasionally  dis¬ 
tinctly  columnar,  and  it  appears  to  have  all  been  poured  out  in  one 
flow,  as  there  are  no  partings  or  divisions  perceptible  in  the  mass, 
which  in  the  vicinity  of  Sonora  is  from  140  to  150  feet  in  thickness. 
Its  width,  at  a  point  near  the  Buckeye  Tunnel,  was  found  to  be  about 


246 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


1700  feet.  The  surface  of  the  basalt  is  very  nearly  level,  with  a  gentle 
slope  down  the  valley,  and  it  is  tolerably  smooth  and  nearly  free  from 
the  rounded,  boulder-like  masses  of  the  same  material  which  almost 
always  cover  the  tops  of  these  Table  Mountains.  As  far  as  examined, 
this  rock  seems  almost  indestructible  by  time.  Hardly  a  trace  of  soil 
has  accumulated  on  it,  and  of  course  only  a  few  bushes  find  a  lodgment 
on  its  surface.  Its  bareness  and  smoothness  give  it  the  appearance  of 
having  been  very  recently  erupted ;  and  yet  how  long  ago  must  this 
event  have  taken  place,  measuring  time  by  anything  except  a  geological 
scale !  It  would  appear  that  the  surface  of  this  lava  flow  has  hardly 
been  worn  away  at  all,  while  the  slates  on  each  side  have  been  eroded 
to  the  depth  of  thousands  of  feet.  The  only  evidences  of  erosion  in 
the  basalt  are  seen  on  its  edges,  which  are  nearly  vertical,  and  which 
have  evidently  resulted  from  the  breaking  off  of  the  volcanic  material, 
as  the  underlying  soft  sedimentary  strata  were  worn  away,  so  as  to 
leave  the  basaltic  rock  overhanging. 

Underneath  the  lava  is  a  heavy  deposit  of  a  detrital  material,  very 
distinctly  stratified  and  lying  nearly  horizontal,  or  with  a  slight  dip 
each  way  towards  the  centre  of  the  mass.  These  sedimentary  beds  are 
of  variable  character,  but  are  chiefly  made  up  of  a  rather  fine-grained 
sandstone,  not  very  closely  compacted,  and  which  rapidly  disintegrates 
on  exposure.  Interstratified  with  this  sandstone,  and  especially  near 
the  bottom  of  the  deposit,  are  fine  argillaceous  shales  and  clays,  nearly 
white  and  often  beautifully  laminated.  With  these  are  beds  of  gravelly 
materials,  strongly  cohering  together,  and  called  “  cement”  by  the 
miners,  and  at  the  bottom  the  “  pay-gravel,”  or  the  “  channel,”  a  body 
of  coarse  gravel,  exactly  like  that  seen  in  the  bed  of  an  ordinary  river. 
The  entire  thickness  of  the  detrital  beds,  directly  under  the  centre  of 
the  lava,  is,  in  one  locality  at  least,  fully  two  hundred  feet.  But  this 
thickness  is  much  less  at  the  edges  of  the  deposit,  owing  to  the  rise  of 
the  auriferous  slates  on  each  side,  forming  what  is  known  everywhere 
in  California  to  the  miners  as  the  “  rim-rock,”  the  position  and  rela¬ 
tions  of  which  may  be  seen  from  the  annexed  section  (Fig.  37),  taken 
at  the  Maine  Boys’  Tunnel,  near  Jeffersonville,  where  a  good  opportu¬ 
nity  was  afforded  for  measuring  the  thickness  of  the  various  rocks  ex¬ 
posed,  and  for  ascertaining  the  position  of  the  top  of  the  rim-rock. 


THE  WESTERN  SLOPE - TUOLUMNE  COUNTY. 


247 


The  lava  is  here  140  feet  thick.  The  rim-rock  rises  fully  150  feet  above 
the  tunnel,  which  is  carried  in  1000  feet,  with  just  sufficient  rise  to 
allow  the  water  to  How  off,  and  at  that  distance  strikes  the  “  channel 


Fig.  37. 


SECTION  AT  MAINE  BOYS’  TUNNEL. 
a.  Rim-rock.  b.  Channel,  c.  Tunnel. 


this  is  here  100  feet  wide,  and  has  a  ledge  of  slate  three  feet  high,  stand¬ 
ing  up  in  the  middle.  The  auriferous  gravel  in  the  channel  is  from 
four  to  five  feet  thick.  It  will  give  some  idea  of  the  cost  and  time 
required  for  opening  a  deposit  of  this  kind,  when  it  is  stated  that  this 
tunnel  was  commenced  in  October,  1855,  and  that  the  pay-gravel  was 
not  struck  until  March,  1860,  the  cost  of  the  work,  up  to  that  time, 
having  been  about  $38,000. 

Another  section  was  made  at  the  Buckeye  Tunnel,  where  the  rela¬ 
tive  position  of  the  different  formations  could  be  seen  on  both  sides  of 
the  mountain,  at  points  nearly  opposite  to  each  other.  The  section 
cannot  be  considered  as  absolutely  correct;  but  a  sufficient  number  of 
measurements  were  made  to  justify  the  statement  that  the  facts  are,  in 
the  main,  about  as  accurately  represented  as  the  scale  of  the  figure  will 
allow.  The  details  of  any  two  tunnels  will  be  found  to  vary  somewhat, 
however  near  they  may  be  to  each  other. 

The  basaltic  lava  forming  the  summit  of  the  mountain  has  a  maxi¬ 
mum  thickness  of  140  feet,  and  is  about  1700  feet  wide.  There  are 
two  channels,  instead  of  one,  and  the  first  was  reached  by  a  tunnel 
going  in  on  the  north  side,  at  a  distance  of  700  feet  from  the  entrance. 
This  channel  was  found  to  be  80  feet  wide,  and  the  miners  extended 
their  works  upwards  into  it  and  took  out  some  of  the  gravel;  but, 
finding  it  not  to  pay  as  well  as  they  had  expected,  they  continued  the 
tunnel  forwards,  in  the  expectation  of  striking  another  channel  (see  sec- 


Fig.  38. 

Section  at  the  Buckeye  Tunnel. 


248 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


O 


\  » 

o3 


tion,  Fig.  38),  of  which  the  posi¬ 
tion  and  character  were  known, 
or  presumed  to  be  known,  from 
the  results  of  other  workings  in 
the  vicinity.  At  the  time  of  our 
visit,  the  tunnel  had  been  driven 
700  feet  beyond  the  first  channel 
towards  the  second,  which  they 
were  in  constant  expectation  of 
reaching. 

A  tunnel  had  also  been  car¬ 
ried  in,  on  the  south  side  of  the 
mountain,  nearly  opposite  the 
one  just  described,  without  hav¬ 
ing  reached  the  channel.  This 
one  was  not  driven  through  the 
rim-rock,  but  was  carried  down 
on  its  surface,  in  the  “cement,” 
with  a  slope  of  thirty-six  feet  in 
one  hundred;  it  had  reached  a 
depth  of  three  hundred  feet 
when  visited,  in  1861. 

The  general  appearance  of 
Table  Mountain,  and  of  the 
sloping  sides  underneath  the 
lava,  with  the  tunnels  driven  in 
through  them,  may  be  seen  in 
the  annexed  wood-cut  (Fig.  39). 

The  tunnels  under  Table 
Mountain  are  usually  run 
through  the  rim-rock,  with  just 
fall  enough  to  drain  the  work¬ 
ings  as  they  are  carried  forward. 
Sometimes,  however,  they  go 
down  on  the  inclined  surface  of 
the  slates,  or  they  are  excavated 


TIIE  WESTERN  SLOPE - TUOLUMNE  COUNTY. 


249 


in  the  soft  sandstone  themselves;  in  such  cases,  the  water  must  he  got 
rid  of  by  pumping.  When  the  channel  is  reached,  it  is  drifted  on, 


Fig.  39. 


TUNNELS  NEAR  TABLE  MOUNTAIN. 


the  miners  following  the  paying  streaks,  or  lines  of  auriferous  gravel, 
up  and  down  in  the  bed  of  the  ancient  water-course.  The  stuff  is 
brought  out  to  the  mouth  of  the  tunnel  in  cars,  and  there  dumped  into 
a  long,  hopper-shaped  box,  from  which  it  is  washed  into  the  sluices,  by 
playing  on  it  with  a  stream  of  water  through  a  hose,  as  in  hydraulic 
mining,  except  that  the  operation  is  on  a  smaller  scale. 

The  stratified  materials  under  the  lava  are  frequently  found  to  con¬ 
tain  masses  of  wood,  and  even  entire  trunks  of  trees.  These  are  very 
commonly  found  under  Table  Mountain,  although  not  as  abundant 
here  as  in  some  of  the  hydraulic  washings  in  other  parts  of  the  State. 
The  wood  is  almost  always  silicified,  being  converted  into  semi-opal,  or 
wood-opal,  as  it  is  frequently  called.  In  this,  the  vascular  structure  is 
often  perfectly  preserved,  and -the  specimens,  especially  such  as  have 
been  partially  carbonized  before  being  fossilized,  are  often  very  beau¬ 
tiful.  In  the  layers  of  finer  sediment,  called  “  pipe-clay”  by  the 
miners,  which  are  very  thinly  and  evenly  bedded,  and  made  up  ot  the 
finest  particles  of  clay,  impressions  of  leaves  are  occasionally  found. 
Neither  the  wood  nor  the  leaves,  from  this  and  similar  localities,  have 


OEOL.  VOL.  T. — 32 


250 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


been,  as  yet,  minutely  examined ;  this  will  be  done,  however,  if  the 
Survey  is  continued,  and  the  results,  with  figures  of  the  different  varie¬ 
ties,  will  be  found  in  the  second  volume  of  the  Palaeontology. 

A  few  specimens  of  the  leaves  from  the  Buckeye  Tunnel  were  for¬ 
warded  to  Dr.  Newberry,  who  has  made  a  preliminary  investigation  of 
them,  furnished  us  with  some  notes  of  his  results,  from  which  we  are 
authorized  to  draw  the  conclusion  that  these  stratified  deposits  under¬ 
neath  the  lava  of  Table  Mountain  are  of  Tertiary  age,  and  that,  in  all 
probability,  they  belong  to  the  later  Pliocene  epoch.  Dr.  Newberry 
remarks,  that  the  leaves  submitted  to  him  are  quite  different  from  those 
of  any  trees  now  growing  in  California,  and  that  they  are  specifically 
distinct  from  those  of  the  Miocene  Tertiaries  of  Oregon,  Nebraska,  or 
any  other  part  of  the  Continent.  They  include  Tertiary  and  recent 
genera,  such  as  Acer  and  Carpinus ,  and  are,  therefore,  not  older  than 
the  Miocene.  They  most  resemble  the  species  found  in  the  later  Eu¬ 
ropean  Tertiaries. 

These  conclusions  in  regard  to  the  age  of  the  formation  in  question 
are  also  rendered  more  probable  by  the  results  of  the  examination  of 
the  bones  and  teeth  of  animals  found,  at  quite  a  number  of  points,  in 
the  strata  underlying  the  lava  of  Table  Mountain  and  similar  volcanic 
overflows. 

Bemains  of  land  and  aquatic  animals  are  frequently  found  in  the 
auriferous  detritus  of  the  State,  and,  not  only  in  the  beds  which  were 
•  deposited  before  the  period  of  intense  volcanic  action,  of  which  the 
crest  and  flanks  of  the  Sierra  in  so  many  places  exhibit  the  most  strik¬ 
ing  proofs,  but  in  the  later  accumulations  of  a  similar  kind,  the  forma¬ 
tion  and  deposition  of  which  has  been  going  on  uninterruptedly  from 
the  close  of  the  Tertiary  period  up  to  the  present  time.  A  large  num¬ 
ber  of  specimens,  of  several  different  genera  and  species,  have  been 
obtained  by  the  Survey  in  various  localities,  or  have  been  examined  in 
the  collections  made  by  others.  These,  remains  consist  of  fragments 
of  bones  and  teeth,  of  which  much  the  larger  portion  are  in  a  very 
poor  condition  for  determination.  Most  of  the  bones,  which  are  dug 
up  or  washed  out  by  the  miners,  fall  to  pieces  on  exposure  to  the  air; 
and  there  is  rarely  any  one  present,  at  the  time  of  their  discovery,  who 
cares  or  understands  how  to  collect  and  preserve  them.  Carelessness 


T1IE  WESTERN  SLOPE - TUOLUMNE  COUNTY. 


251 


and  idle  curiosity  lead  to  the  destruction  of  most  of  the  hones  which 
are  in  a  condition  to  resist  the  action  of  the  elements;  while  it  is  also 
true  that,  in  many  cases,  the  fragments  which  are  lucky  enough  to  be 
preserved  by  the  miners,  are  regarded  by  them  as  of  immense  value, 
and  cannot  be  secured,  at  anything  like  a  fair  price,  for  the  purposes  of 
scientific  description. 

There  is  another  difficulty  in  getting  at  the  character  of  the  Fauna  of 
the  auriferous  gravels  and  other  superficial  formations.  The  localities 
of  specimens  obtained  are  frequently  uncertain ;  and,  even  if  the  exact 
spot  where  the  fossil  was  found  happens  to  be  known,  it  is  often  quite 
impossible  to  decide  whether  it  originally  belonged  to  the  stratum  in 
which  it  was  found,  or  whether  it  may  not  have  been  washed  out  from 
an  older  bed.  From  what  has  been  said  in  the  previous  pages,  it  will 
be  seen  what  an  immense  amount  of  erosion  of  the  surface  has  taken 
place  since  the  volcanic  outbreaks  in  the  Sierra,  and  it  will  easily  be 
recognized  that  many  skeletons  of  animals,  originally  buried  under  the 
lava,  must  have  been  torn  from  their  beds  and  distributed  far  and  wide 
over  the  country. 

In  spite  of  these  difficulties,  we  think  we  have  clearly  made  out  that 
there  are  two  distinct  epochs  represented  by  the  animal  remains  found 
in  the  auriferous  detritus.  The  beds  which  were  deposited  prior  to 
the  great  volcanic  disturbances  and  consequent  overflows  of  lava, 
throughout  the  Sierra,  inclose  a  peculiar  Fauna,  which  we  refer  to  the 
Pliocene  epoch,  and  which  appears  to  have  some  analogy  with  the  group 
of  the  same  age,  occurring  on  the  Niobrara  and  White  Rivers,  and  in 
their  vicinity,  to  the  east  of  the  Rocky  Mountain  chain,  where  such  an 
immense  profusion  of  vertebrate  remains  have  been  found  by  Dr.  Hay¬ 
den  and  other  zealous  explorers,  and  which  have  been  investigated 
with  such  consummate  skill  by  Dr.  Leidy. 

Among  the  animals  of  the  Pliocene  of  California,  or  the  group  which 
preceded  the  epoch  of  volcanic  activity,  we  recognize  the  rhinoceros, 
an  animal  allied  to  the  hippopotamus,  an  extinct  species  of  horse,  and  a 
species  allied  to  the  camel  and  resembling  the  Megalomeryx  of  Leidy  ; 
all  these  species,  so  far  as  we  know,  are  peculiar  to  the  deposits  under 
the  lava,  and,  as  would  be  expected,  they  did  not  survive  the  grand 


252  GEOLOGY  OF  THE  SIERRA  NEVADA. 

catastrophe,  by  which  the  forests  and  streams  in  which  they  lived,  and 
to  which  they  resorted,  were  overwhelmed  and  annihilated. 

After  the  close  of  the  period  of  volcanic  activity,  a  new  Fauna  made 
its  appearance  on  the  slopes  and  amid  the  foot-hills  of  the  Sierra.  This 
Fauna  belongs  to  the  Post-Pliocene  epoch,  and  passes  gradually  into 
that  of  the  present  day,  or  the  Recent.  Prominent  among  the  animals 
of  that  time  were  the  mastodon  and  elephant,  whose  remains  are  found 
in  the  greatest  abundance  in  the  superficial  detritus  of  the  gold  region; 
but  never,  so  far  as  we  have  been  able  to  ascertain,  in  the  deposits 
under  the  lava.  Associated  with  these  proboscidians,  were  the  tapir, 
the  bison  (buffalo),  and  the  horse,  the  latter  animal  being  very  abun¬ 
dant  and  represented  by  two  species,  of  which  one  is  not  to  be  distin¬ 
guished  from  the  present  mustang,  or  Indian  horse.* 

In  terminating  this  digression,  it  may  be  proper  to  add,  that  the 
works  of  man  have  been  frequently  found  among  the  recent  deposits  of 
auriferous  gravel,  and  in  such  close  connection  with  the  bones  of  the 
mastodon  and  elephant,  that  it  is  hardly  possible  to  escape  the  infer¬ 
ence  that  the  human  race  existed  before  the  disappearance  of  these 
animals  from  the  region  which  was  once  so  thickly  inhabited  by  them. 
Other  facts,  long  since  collected  by  geologists  in  different  parts  of 
this  country,  have  pointed  most  significantly  in  the  direction  of  this 
conclusion,  and  the  investigations  of  the  last  few  years  in  Europe  have 
made  it  certain  that  the  same  association  of  man  with  animals  belong¬ 
ing  to  species  now  extinct  formerly  existed  there.  Thus  the  researches 
of  scientific  men,  on  both  sides  of  the  Atlantic,  concur  in  giving  to  the 
human  race  a  much  greater  antiquity  than  had  been  previously  assigned 
to  it,  a  conclusion  which  was  so  contrary  to  the  popular  belief,  that  it 
would  not  have  been  adopted  had  not  the  evidence  in  its  favor  been 
ample  and  conclusive. 


*  Our  collection  of  vertebrate  remains  has  been  referred  to  Dr.  Leidy,  who  has  fur¬ 
nished  a  list  of  the  same,  and  described  such  as  were  new  in  the  Proceedings  of  the  Phila¬ 
delphia  Academy  of  Natural  Sciences  for  the  year  1865.  All  our  collections  in  this 
department  will  be  worked  up  by  him  for  the  second  volume  of  the  Palaeontology.  The 
whole  subject  of  the  Fauna  of  the  Tertiary  and  Post-Tertiary  of  the  Pacific  coast  will  be 
thoroughly  treated  in  a  future  volume  of  this  Report;  before  which,  we  trust  that  con¬ 
siderable  additions  will  have  been  made  to  our  stock  of  materials. 


TIIE  WESTERN  SLOPE - CALAVERAS  COUNTY. 


OCQ 

Zoo 


Iii  the  vicinity  of  Soulsbyville,  six  miles  east  of  Sonora,  is  another 
series  of  volcanic  deposits,  which  have  not  been  traced  to  their  origin 
in  the  High  Sierra;  but  which  very  probably  are  the  termination  of  one 
of  the  lava  streams  which  originated  in  the  great  volcanic  region  to¬ 
wards  the  upper  part  of  the  Sonora  road  to  Aurora,  and  where,  over  a 
wide  area,  lava  caps  nearly  all  the  highest  points.  As  exposed  near 
Soulsbyville,  the  solid  lava,  which  is  about  fifty  feet  thick,  lies  upon  a 
heavy  stratum  of  volcanic  ashes  and  pumice-stone,  which  has  evidently 
been  washed  down  the  Sierra,  and  deposited  in  a  more  or  less  perfectly 
stratified  form.  Under  this,  is  a  bed  of  fine  clay,  “  pipe-clay”  of  the 
miners,  from  eight  to  ten  feet  thick.  This  again  rests  on  the  bed-rock, 
which  is  granite,  very  much  decomposed.  Here  also  bones  and  teeth 
have  been  found  under  the  lava,  including  those  of  an  extinct  species 
of  horse,  as  noticed  above. 


Section  V. — Calaveras  County. 

The  boundaries  of  Calaveras  County  are,  the  Stanislaus  River  on 
the  southeast,  and  the  Mokelumne  on  the  northwest,  the  distance  be¬ 
tween  the  two,  in  the  mining  region,  being  from  twenty-four  to  thirty 
miles.  Quite  an  extensive  range  of  mountains,  called  the  Bear  Moun¬ 
tains,  runs  from  the  Stanislaus  nearly  to  the  Calaveras  River,  and 
divides  the  district  in  question  into  two  rather  distinct  portions,  of 
which  the  lower  or  southwestern  belongs  to  the  foot-hills,  the  upper  to 
the  Sierra  proper.  The  region  of  the  foot-hills  is  pre-eminently  the 
copper  mining  district  of  the  State,  while  a  belt  about  twelve  miles 
wide  on  the  other  side  of  the  Bear  Mountains  is  one  of  the  richest  por¬ 
tions  of  the  gold  region.  The  foot-hills  are  very  dry,  there  being  no 
streams  which  are  permanent  through  the  summer,  excepting  the  Ca¬ 
laveras,  of  which  the  water  is  pretty  much  all  used  up  for  mining  pur¬ 
poses,  before  it  leaves  the  gold  region.  The  numerous  branches  of  this 
river  drain  the  district  between  the  Stanislaus  and  the  Mokelumne 
during  the  rainy  season,  running  mostly  in  deep  canons  between  spurs 
of  the  Sierra,  and  their  water  is  utilized  for  gold  washing,  as  long 
as  it  lasts,  by  an  elaborate  system  of  ditches.  For  a  permanent  source 


254 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


of  supply  during  the  whole  summer,  however,  recourse  has  to  he  had 
to  the  canals,  or  ditches,  as  they  are  always  called  in  California,  which 
head  in  the  very  highest  portions  of  the  Sierra,  as  none  of  those  do 
which  are  connected  with  the  Calaveras. 

The  towns  which  have  been  built  up  by  the  gold  mining  business, 
and  which  still  depend  chiefly  on  that  for  their  prosperity,  are  stretched 
along  a  belt  running  in  a  northwest  and  southeast  direction  through 
the  county,  and  are  ranged  in  two  parallel  lines  six  or  eight  miles  apart. 
The  southwestern  series  includes  Angel’s,  Upper  and  Lower  Calaveras 
Camps,  and  Mokelumne  Hill ;  the  other,  Murphy’s,  Cave  City,  and  El 
Dorado.  On  the  first-mentioned  range  there  has  been,  and  is  still,  a 
good  deal  of  quartz  mining,  while  along  the  other  line  the  placer  mines 
constitute  almost  the  exclusive  interest ;  but,  as  there  has  been  a  great 
falling  oft*  in  the  yield  of  the  surface  diggings  within  the  last  few  years, 
some  of  the  camps  appear  to  be  entirely  deserted. 

In  the  central  portion  of  Calaveras  County,  the  belt  of  metamorpliic 
rocks  of  the  Sierra  system,  or  the  auriferous  slate  series,  occupies  a 
width,  northeast  and  southwest,  of  about  twenty-four  miles.  In  its 
southwestern  portion  it  is  hardly  covered  at  all  by  other  formations, 
excepting  that  of  the  superficial  detritus;  but  on  the  northwest,  to¬ 
wards  their  junction  with  the  granite,  the  auriferous  slates  are  very 
extensively  overlain  by  the  volcanic  beds  which  play  so  important  a 
part  in  the  geology  of  the  Sierra  Nevada.  All  the  region  between  the 
Bear  Mountain  Range  and  the  base  of  the  foot-hills,  from  the  Stanis¬ 
laus  to  the  Calaveras,  is  nearly  of  one  character,  consisting  of  low  roll¬ 
ing  hills,  not  very  regular  in  direction  or  continuous,  with  many  valleys, 
which  would  be  most  delightful  if  better  supplied  with  water.  The 
district  to  the  north  of  the  range  is  also  deficient  in  this  respect,  but 
having  the  advantage  of  the  artificial  supply  from  the  ditches,  portions 
of  it  are  well  cultivated,  and  are  especially  productive  in  fruit. 

The  upper  mining  district,  of  which  the  town  of  Copperopolis  is  the 
headquarters,  extends  across  from  the  Stanislaus  to  the  Calaveras ;  but 
the  principal  productive  mines  are  at  the  eastern  extremity  of  the 
range,  not  far  from  the  head  of  Black  Creek,  an  insignificant  branch 
of  the  Stanislaus.  Claims  have  been  taken  up  in  this  region  chiefly  in 
two  nearly  parallel  lines  five  or  six  miles  apart,  of  which  one  runs  along 


TI1E  WESTERN  SLOPE - CALAVERAS  COUNTY. 


255 


the  base  of  the  Bear  Mountain  Range,  and  the  other  follows  a  broken 
range  of  hills,  called  the  Gopher  Hills.  The  first  of  these  ranges  is  on 
what  is  called,  from  its  discoverer,  the  “  Reed  Lode,”  and  claims  have 
been  taken  up  on  it  for  a  length  of  about  twelve  miles,  in  a  remarkably 
regular  sequence,  the  general  direction  of  the  productive  part  of  this 
lode  being  K.  30°  W.  This  line  of  claims  curves  very  gently  to  the 
northward  as  it  goes  west.  The  other  line  is  much  more  irregular, 
indicating  great  uncertainty  in  following  the  outcrop,  and  it  does  not 
appear  that  anything  of  importance  has  been  discovered  on  it,  except  at 
its  eastern  end,  although  the  length  of  the  line  along  which  claims 
have  been  made  is  fifteen  miles  or  more. 

The  deposits  of  copper  ore  in  this  region,  like  nearly  all  the  others 
in  California,  do  not  appear  to  be  included  in  regular  fissure  veins,  but 
rather  to  form  independent  masses  lying  in  the  direction  of  the  strike 
of  the  inclosing  rocks,  and  dipping  with  them.  The  metalliferous 
portion  is  not  usually  separated  from  the  wall-rock  by  two  regular  sel¬ 
vages,  nor  is  it  accompanied  by  any  considerable  amount  of  veinstone 
of  a  peculiar  character  and  clearly  distinguishable  from  the  formation 
in  which  it  is  inclosed.  But,  if  not  exhibiting  all  the  characters  of  true 
veins,  these  metalliferous  deposits  are  sometimes  of  enormous  dimen¬ 
sions  and  of  remarkable  purity. 

The  Reed  Lode  was  discovered  by  Mr.  W.  K.  Reed,  July  4th,  1861, 
and  the  first  house  built  at  what  is  now  the  thriving  town  of  Copperop- 
olis,  September  5th.  The  outcrop,  along  where  are  now  the  Union 
and  Keystone  Mines,  was  very  marked,  and  considerable  quantities  of 
the  oxidized  ores  of  copper  were  obtained  near  the  surface,  as  well  as 
fine  specimens  of  native  copper  in  arborescent  crystalline  forms;  some 
of  the  masses  of  malachite  were  very  handsome,  and  there  was  a  large 
quantity  of  impure  black  oxide  (copper-smut)  obtained,  mixed  with 
more  or  less  of  the  red  oxide.  These  oxidized  combinations  all  give 
out  at  the  depth  of  twenty  or  thirty  feet,  and  the  sulphuret  (chalcopy- 
rite,  the  yellow  ore  of  the  miners)  takes  their  place.  There  is  some 
iron  pyrites  mixed  with  the  copper  pyrites,  even  when  the  latter  ap¬ 
pears  pure,  as  the  percentage  of  the  ore  does  not  come  quite  up  to  that 
required  by  the  formula,  although  no  mechanical  intermixture  of  foreign 
ingredients  can  be  detected  by  the  eye. 


2  50 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


The  rocks  inclosing  the  lode  near  Copperopolis  are  chiefly  chlorite 
and  clay-slates,  passing  in  places  into  hornblende-slate  and  hornblende- 
rock.  Farther  west  there  are  very  heavy  beds  of  serpentine,  in  the 
line  of  strike  of  the  vein,  and  with  indications  of  copper  disseminated 
through  the  mass  of  the  rock. 

The  two  principal  mines  at  Copperopolis  are  the  “  Union”  and  the 
“Keystone;”  both  of  these  are  opened  on  an  extensive  scale,  and  have 
been  shipping  large  quantities  of  ore  for  a  considerable  time.  It  will 
not  be  possible  to  give  a  detailed  description  of  these  mines,  as  that 
belongs  properly  in  the  volume  of  Economical  Geology,  and  they  have 
not  been  examined  by  us  with  minuteness,  since  they  attained  their 
present  development.  A  few  items  may,  however,  be  given,  to  show 
the  great  value  of  this  cupriferous  region,  and  to  give  an  idea  of  its 
importance  to  the  State. 

The  Union  Mine  would  appear  to  be  opened  on  one  of  the  largest 
deposits  of  ore  ever  struck  in  any  part  of  the  world,  and  the  shipments 
from  it  have  been,  during  the  last  year  or  two,  on  an  immense  scale. 
We  regret  not  being  able  to  give  the  exact  figures  for  the  whole  time 
since  tne  mine  was  opened;  but  it  appears  that  over  10,000  tons  of  first 
and  second  class  ores  were  forwarded  to  San  Francisco  from  March  to 
July  of  the  current  year.  In  June,  1865,  the  shipments  amounted  to 
3600  tons,  and  they  were  expected  to  be  equally  as  large  in  July.  The 
yield  of  the  Ko.  1  ore,  we  suppose  to  be  about  twenty-four  per  cent, 
(at  least,  this  was  the  percentage  in  1862),  and  about  an  equal  amount 
of  the  two  grades  has  been  shipped  of  late.  When  examined  by  us, 
in  1862,  there  was  to  be  seen  in  this  mine  a  mass  of  ore,  apparently 
quite  free  from  any  intermixture  of  barren  rock,  and  of  which  the 
dimensions  were  not  less  than  three  hundred  feet  in  length  and  sixty 
feet  high,  while  the  average  width  could  not  have  been  less  than  five 
feet,  and  there  were  portions  fully  nine  feet  across,  with  only  a  thin 
seam  of  rock  in  the  centre  a  few  inches  in  width. 

We  learn  that  the  principal  shaft  of  this  mine  had,  in  July,  1865, 
reached  a  depth  of  400  feet,  the  lowest  level  driven  in  the  lode  being 
at  300  feet  from  the  surface.  At  the  200-foot  level,  the  lode  is  21 
feet  wide ;  at  the  250-foot,  31  feet,  and  composed  almost  wholly  of 


THE  WESTERN  SLOPE  —  CALAVERAS  COUNTV.  257 


Nos.  1  and  2  ores.*  There  are  now  about  350  men  employed  at  this 
mine.  ^ 

The  Keystone  Mine  is  also  in  a  prosperous  condition,  having  a  large 
amount  offgood  stoping-ground  opened,  dressing  works  in  successful 
operation,  and  bidding  fair  to  he,  at  no  distant  day,  not  far  behind  the 
Union  in  the  amount  of  its  shipments. 

The  growing  importance  of  the  copper  mining  interests  of  the  State 
may  be  inferred  from  the  fact  that  the  shipments  of  ore  amounted,  in 
1863,  to  5933  tons,  valued  at  $512,925,  and  in  1864  to  14,315  tons,  value 
$1,094,660.  Of  these  amounts  very  much  the  larger  portion  was  de¬ 
rived  from  the  mines  at  Copperopolis. 

There  are  several  other  mines  at  work  in  this  vicinity,  some  of 
which  may  become  paying  concerns,  if  managed  with  skill  and  energy. 
Of  the  hundreds  of  claims  located  in  this  region,  but  few  have  had 
any  serious  work  done  on  them ;  and  it  must  be  distinctly  borne  in 
mind  that  the  occurrence  of  an  unprecedentedly  large  mass  of  ore 
in  the  Union  and  Keystone  Mines,  does  not  necessitate  the  existence  of 
others  in  the  same  mineral  channel  on  either  side;  such  bodies  of  rich 
metalliferous  material  must  be  looked  on  as  quite  exceptional.  The 
establishment  of  smelting  works  on  the  Pacific  coast  will  in  time 
allow  of  the  utilization  of  a  lower  grade  of  ore  than  can  at  present  he 
shipped  with  profit  to  the  Atlantic  States  or  to  England ;  and  increased 
facilities  of  communication,  especially  the  building  of  railroads  from 
tide-water  up  into  the  mining  districts  of  the  Sierra,  will  enable  many 
mines  to  be  successfully  worked,  which  at  present  must  languish,  on 
account  of  their  distance  from  a  port  of  shipment.  There  can  be  no 
doubt  that  California  is  destined  to  take  a  very  high  rank  as  a  copper- 
producing  State,  in  spite  of  the  difficulties  which  scarcity  of  fuel  and 
cost  of  transportation  throw  in  the  way  of  the  development  of  the  min¬ 
ing  interests,  in  all  cases  where  the  bulk  of  the  product  is  large  in  pro¬ 
portion  to  its  value,  as  is  the  case  with  all  but  a  few  of  the  metals. 

There  is  another  group  of  copper  mines  in  Calaveras  County,  between 
the  Calaveras  and  Mokelumne  Rivers,  near  Camp  Seco.  This  range 


A 


*  For  the  facts  here  given  which  have  reference  to  the  present  condition  of  the  Union 
and  Keystone  Mines,  we  are  indebted  to  the  kindness  of  H.  H.  Sheldon,  Esq.,  the  skillful 
superintendent  of  the  latter. 

QEOL.  VOL.  I. — 33 


258 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


seems  to  be  almost  exactly  in  the  line  of  the  trend  of  the  Copperopolis 
mines.  When  examined,  in  1863,  there  was  considerable  activity  at 
several  mines  in  this  vicinity,  the  conditions  being  similar  to  those 
indicated  above  as  common  to  most  of  the  cupriferous  de^psits  of  the 
State.  The  ore  seems  a  good  deal  mixed  with  iron  pyrites,  by  which 
its  percentage  is  considerably  reduced ;  on  assaying  some  of  the  sam¬ 
ples,  it  was  found  that  it  was  impossible  to  form  a  correct,  opinion  of 
the  yield  of  the  ores  from  this  district  by  simple  inspection.  The  depo¬ 
sits  of  ore  here  are  evidently  quite  large,  and  would  be  of  high  impor¬ 
tance  in  a  region  where  labor  and  fuel  were  not  so  scarce  and  high. 
At  the  Lancha  Plana  mine,  when  visited  in  August,  1863,  a  shaft  had 
been  sunk  150  feet,  and,  although  little  or  nothing  had  been  done  in 
driving  from  it,  120  tons  of  ore  had  been  shipped,  and  200  more  lay  on  the 
surface,  the  vein  being  about  four  feet  in  thickness.  The  ore  appeared 
rich  to  the  eye;  but  whether  sufficiently  so  to  pay,  at  present,  the 
heavy  cost  of  shipment  to  the  Atlantic  States,  or  England,  had  not  then 
been  ascertained.  At  the  Copper  Hill  claim,  a  shaft  had  been  sunk  on 
the  vein  to  the  depth  of  250  feet ;  the  lode  was  two  feet  wide,  and  con¬ 
sisted  of  a  mixture  of  iron  and  copper  pyrites,  but  was  not  very  rich  in 
copper.  Of  the  present  condition  of  these  mines  nothing  definite  is 
known  ;  that  they  will  eventually  become  of  importance  can  hardly  be 
doubted,  although  the  ore  may  be  of  too  low  a  grade  to  be  mined  with 
profit  under  the  present  conditions. 

Passing  to  the  north  of  the  Bear  Mountain  Range,  we  find  essen¬ 
tially  the  same  character  of  geological  formations  which  has  already 
been  noticed  as  existing  in  Tuolumne  County.  The  region  from 
Angel’s  to  Mokelumne  Hill  is  almost  a  repetition  of  that  between  Big 
Oak  Flat  and  Columbia.  We  have  the  auriferous  slate  series,  with  a 
wide-  and  broken  belt  of  limestone  on  the  north,  succeeded,  in  that 
direction,  by  the  granitic  masses  of  the  High  Sierra.  As  in  Tuolumne, 
so  here,  the  volcanic  and  sedimentary-volcanic  formations  play  a  great 
part,  and  cover  very  extensive  areas 'of  the  gold-bearing  slates,  and  are 
themselves  worked  in  many  places  by  the  hydraulic  method. 

The  average  trend  of  the  auriferous  slates  in  Calaveras  is  more 
northerly  than  in  Tuolumne ;  but  there  are  many  deflections  from  a 
straight  line,  and  large  bodies  of  strata  run  nearly  due  east  and  west. 


THE  WESTERN  SLOPE - CALAVERAS  COUNTY. 


259 


Judging  from  the  position  of  the  outcrops  of  the  limestone  belt  between 
Abby’s  Ferry  and  Cave  City,  the  mean  trend  of  the  formations  through 
that  part  of  the  county  is  N.  20°  E.,  which  direction  appears  to  be 
continued  on  as  far.  as  Volcano  in  Amador  County,  where  .the  lime¬ 
stone  crops  out  again. 

The  line  of  separation  between  the  metamorphic  slates  and  the  gra¬ 
nitic  formations  on  the  north  has  not  been  traced  out ;  but,  as  noticed 
at  various  points,  there  appears  to  be  a  considerably  greater  width  of 
metamorphic  strata  between  the  limestone  and  the  granite  than  there 
is  in  Tuolumne.  The  belt  of  rock  which  occupies  that  position  consists 
of  coarse  silicious  slates,  with  some  mica,  and  occasional  bands  of  a 
gneissoidal  rock.  These  strata  do  not  appear  to  be  auriferous,  as 
there  are  hardly  any  mining  camps  of  importance  on  the  north  of  the 
limestone. 

The  limestone  belt  is  first  seen  in  coming  into  the  county  from  Tuo¬ 
lumne,  in  the  vicinity  of  Douglass  Flat,  a  little  east  of  Murphy’s.  The 
strike  of  the  slates  at  Silver  Knoll,  tliree-fourtlis  of  a  mile  northwest  of 
Douglass  Flat,  is  nearly  east  and  west,  the  rocks  having  evidently 
undergone  great  disturbances  in  this  region,  so  that  the  continuity  of 
the  limestone-belt  is  broken  in  several  places  between  here  and  Cave 
City;  it  now  appears  to  consist  of  immense  detached  masses  lying  in 
an  east  and  west  direction,  and  entirely  cut  off  from  all  connection  with 
each  other.  At  Murphy’s,  the  limestone  forms  a  lofty  and  picturesque 
outcrop  of  dark,  bluish-gray  color,  nearly  bare  of  vegetation ;  this 
elevation  rises  on  the  east  and  north  of  the  town,  which  is  also  under¬ 
lain  by  the  same  rock,  worn  into  deep  cavities  filled  with  auriferous 
detritus,  and  resembling  those  described  as  occurring  near  Columbia ; 
here,  also,  it  is  extensively  and  profitably  worked.  The  belt  of  lime¬ 
stone  at  Murphy’s  is  about  a  mile  and  a  quarter  wide ;  it  has  on  its 
southern  border  slate,  which  contains  numerous  quartz  veins  and  dips 
to  the  northeast  at  an  angle  of  70°.  To  the  north,  the  limestone  passes, 
through  an  intermediate  stage  of  calcareous  sandstone,  into  a  silicious 
slate.  Kear  the  line  of  contact  between  the' limestone  and  slates,  on 
this  side,  are  quite  extensive  deposits  of  hematite  iron  ore,  which  have 
not  been  opened  or  worked  at  all,  and  whose  exact  extent  cannot  there¬ 
fore  be  known.  Were  fuel  abundant  and  labor  cheap,  this  deposit 


260 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


might  become  of  importance.  Under  present  conditions,  this  is  hardly 
possible. 

The  limestone  belt  in  the  vicinity  of  Murphy’s  is  remarkable  as  con¬ 
taining  quartz  veins  of  sufficient  size  and  richness  to  have  been  worked 
quite  extensively  at  different  times.  At  the  Blue  Wing  Mill,  three- 
fourths  of  a  mile  north  of  Murphy’s,  a  vein  of  quartz  occurs  in  this 
position,  and  was  mined  quite  extensively  for  some  time.  The  vein  is 
well-defined,  is  about  two  feet  wide,  and  runs  obliquely  across  the  lime¬ 
stone,  as  nearly  as  could  he  made  out;  hut  the  stratification  is  so  dis¬ 
turbed  that  the  relative  position  of  the  lode  and  the  inclosing  rock 
could  not  he  satisfactorily  determined.  The  rock  from  this  vein  paid 
handsomely  near  the  surface,  yielding  as  much  as  $80  a  ton.  The 
strike  of  the  limestone  near  the  mill  is  hT.  80°  E.,  and  its  dip  is  to  the 
southeast  at  an  angle  of  65°  to  70°.  It  will  thus  be  seen  how  entirely 
the  dip  and  strike  of  this  mass  of  rock  separate  it  from  other  portions 
of  the  same  formation  north  and  south.  The  outcrop  continues  for 
some  distance  in  the  high  hills  between  Murphy’s  Creek  and  the  San 
Domingo,  and  is  very  conspicuous,  at  a  distance,  from  the  peculiar 
color  of  the  rock.  In  this  vicinity  is  an  interesting  vein  in  the  lime¬ 
stone,  called  the  Green  Bock  Ledge;  this  vein  is  inclosed  in  thin- 
bedded  calcareous  slate,  or  slaty  limestone,  which  runs  almost  exactly 
east  and  west,  and  dips  to  the  north  at  an  angle  of  70°.  The  vein  has 
a  direction  nearly  at  right-angles  to  this,  and  dips  at  an  angle  of  36° ; 
its  width  is  about  two  feet  where  opened.  The  veinstone,  which  as- 
sa}'ed  well  for  gold  at  the  surface,  also  contained  cinnabar  in  small 
quantity,  together  with  traces  of  vitreous  copper  ore,  and  some  blue 
and  green  carbonate  of  copper.  This  is  one  of  the  very  few  localities 
where  an  ore  of  mercury  has  been  found  in  rocks  belonging  to  the 
Sierra  series. 

Passing  from  the  San  Domingo  Creek  northwest  of  Murphy’s,  in  the 
direction  of  Cave  City,  the  limestone  belt  disappears  altogether,  so  far 
as  could  be  ascertained ;  and,  although  this  last-mentioned  place  is 
about  in  the  line  of  the  average  strike  of  the  limestone  through  this 
part  of  the  State,  or  27.  20°  W.  from  Murphy’s,  still,  in  travelling  be¬ 
tween  the  two  places,  no  traces  of  its  existence  were  discovered  until 
we  approached  within  about  a  mile  of  Cave  City,  where  its  outcrop  is 


THE  WESTERN  SLOPE  —  CALAVERAS  COUNTY.  261 


very  conspicuous.  Here  the  strata  have  their  usual  trend  of  about 
H.  25°  to  30°  W.,  and  dip  northeast  at  an  angle  of  60°.  The  masses 
of  limestone  rise  in  hare  and  precipitous  ridges,  which  are  picturesque 
in  outline,  and  quite  striking,  on  account  of  their  light  bluish-gray 
color,  which  contrasts  in  such  a  marked  way  with  the  reddish-browns 
of  the  auriferous  slate-formation.  From  this  point  the  outcrop  of 
limestone  may  be  traced  northwest  and  southeast  for  a  mile  or  more  in 
each  direction.  Beyond  this  to  the  northwest,  it  has  not  been  seen 
again  by  us  anywhere  to  the  southeast  of  Volcano. 

Cave  City,  which  is  about  twelve  miles  south-southeast  of  Moke- 
lumne  Hill,  is  noted  for  its  extensive  cave  in  the  limestone  rock;  this 
is  well  worth  seeing,  and  would  be  more  frequently  visited  if  decent 
accommodations  could  be  had,  which  was  not  the  case  in  1863.  The 
cave  has  all  the  usual  features  of  such  places, — long  winding  passages 
opening  into  wide  chambers,  beautifully  ornamented  with  stalactites, 
and  it  is  said  to  have  been  traced  more  than  half  a  mile  in  its  windings. 
A  visit  may  be  made  to  it  from  Murphy’s,  there  and  back  in  one  day, 
over  a  rough  trail  crossing  three  high  ridges  and  passing  through  a 
picturesque  and  finely  wooded  region.  Those  who  have  never  visited 
a  large  cave  should  see  this  one,  when  on  their  way  to  or  from  the  Big 
Trees. 

The  great  quartz  vein  of  California  appears  to  be  continued  across 
the  county  of  Calaveras,  entering  it  at  Robinson’s  Ferry,  making 
itself  very  conspicuous  at  Carson  Hill,  appearing  again  on  Albany  Hill, 
and  then  at  Angel’s.  It  is  seen  again  between  that  place  and  San  An¬ 
dreas,  and  once  more  a  little  to  the  northwest  of  San  Andreas.  Beyond 
this  it  has  not  been  recognized  anywhere  southeast  of  Jackson.  It 
has  been  extensively  worked  at  several  points,  especially  on  Carson 
Hill  and  near  Angel’s,  quartz-mining  having  been  at  one  time  in  this 
county  a  much  more  important  business  than  it  now  is.  Mr.  Ashbur- 
ner’s  notes,  made  in  1861,  give  the  following  information  in  regard  to 
the  condition  of  the  quartz  mills  in  that  year. 

Angel’s  Camp  was  formerly  a  very  active  quartz-mining  centre, 
there  having  been  thirteen  mills  in  operation  in  its  vicinity.  In  1861, 
there  were  only  three  or  four  at  work;  and  in  1863,  only  two.  In 
1861,  the  most  important  mill  was  the  “  Crystal  Mill,”  built  in  1857, 


2G2 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


having  twelve  stamps,  run  by  steam,  and  stamping  dry.  This  is  one 
of  the  few  quartz  mills  in  the  State  where  the  Freiberg  barrels  were  in 
use  in  the  amalgamating  processes.  It  was  running  on  custom-work  in 
1861,  and  was  closed  in  1863. 

The  “  Cornish  Mill,”  built  in  1860,  was  running,  in  1860,  on  quartz 
which  paid  only  about  $4  a  ton.  The  “  Angels’  Quartz-Mining  Com¬ 
pany’s”  Mill,  built  in  1857,  had  sixteen  stamps,  and  was  run  by  steam ; 
as  worked  in  1861,  the  rock  crushed  yielded  about  $5  a  ton. 

The  mills  at  Angel’s  were  all  built  to  run  on  rock  taken  from  a  side 
vein  about  two  hundred  feet  northeast  of  the  great  quartz  vein,  which 
is  here  very  wide  and  prominent,  forming  a  very  conspicuous  outcrop 
on  the  summit  of  the  hill.  The  mines  have  been  extensively  worked 
in  a  series  of  open  cuts,  from  six  to  twelve  feet  wide,  and  for  a  length 
of  about  a  third  of  a  mile.  The  masses  of  quartz  lie  parallel  with 
each  other  and  form  belts  in  the  talcose  slate.  The  amount  of  mate¬ 
rial  which  can  be  obtained  here  is  large;  but  its  yield  is  low.  At  Fos¬ 
ter  &  Co.’s  Mill,  it  was  said,  in  1863,  to  be  paying  $6  a  ton.  It  is  a 
question  whether,  by  the  introduction  of  improved  machinery  for 
saving  the  gold,  these  mines  may  not  yet  be  made  of  great  importance. 

The  vicinity  of  Carson  Hill  is  classic  ground  in  the  history  both  of 
quartz  and  placer  mining  in  this  State.  It  would  be  hard  to  point  out 
any  spot  in  the  Gold  Region  where  richer  placers  or  more  astonishing 
masses  of  gold-bearing  quartz  have  been  found  than  in  the  immediate 
vicinity  of  Carson  Hill ;  and  yet,  such  is  the  apparent  irregularity  of 
the  veins,  that,  thus  far,  all  efforts  to  make  gold-mining  a  permanent 
and  profitable  business  at  that  place  have  failed. 

The  great  quartz  vein,  in  coming  from  Angel’s,  crops  out  a  little 
before  reaching  the  summit  of  Albany  Hill,  which  it  there  crosses  over, 
with  a  nearly  southeast  course,  being  a  very  conspicuous  object,  like 
the  outcrop  on  the  Peiion  Blanco.  It  branches  to  the  southeast  and 
disappears  as  it  descends  the  side  of  the  hill,  but  rises  again  on  the  east 
side  of  Carson  Creek  and  forms  the  crest  of  Carson  Hill  for  a  distance 
of  about  a  third  of  a  mile ;  here  its  strike  is  about  H.  55°  W.  Going 
down  the  southeast  side  of  the  hill,  the  vein  seems  again  to  be  lost;  the 
heavy  outcrop  of  quartz  reappears,  however,  in  a  line  parallel  with  the 
outcrop  on  Carson  Hill,  but  a  third  of  a  mile  to  the  southwest,  as  if  the 


THE  WESTERN  SLOPE - CALAVERAS  COUNTY. 


263 


vein  had  been  thrown  in  that  direction  hy  the  movements  of  the  strata. 
This  outcrop  is  on  the  summit  of  the  Santa  Cruz  Hill,  which  runs 
down  to  the  StaiTislaus  at  Robinson’s  Ferry.  There  are  also  masses  or 
irregular  veins  of  quartz  running  north  from  near  the  southeastern  end 
of  the  Santa  Cruz  Hill,  several  parallel  north  and  south  claims  having 
been  taken  up  here;  one  of  these,  the  Stanislaus  Mine,  has  been  quite 
extensively  worked,  and  has  furnished  some  of  the  most  striking  speci¬ 
mens  of  rich  gold-bearing  rock  ever  found  in  the  State.  Associated 
with  the  gold  are  the  tellurides  of  silver  and  gold,  in  much  larger  quan¬ 
tity  than  these  rare  substances  have  ever  yet  been  found  at  any  other 
locality  in  this  country  so  far  as  known.*  Quite  extensive  explorations 
have  been  made  at  this  place  by  shafts  and  drifts,  showing  here  and 
there  rich  hunches  of  gold-bearing  quartz,  but  of  which  the  connection 
is  not  easily  to  be  made  out.  A  most  systematic  and  careful  explora¬ 
tion  is  required  here,  to  settle  the  question  whether  the  vein  is  continu¬ 
ous  and  regular  enough  to  he  worked  with  profit. 

A  great  many  places  have  been  opened  on  the  summit  of  Carson 
Hill,  and  gold  has  been  found  disseminated  very  irregularly  through 
the  rocks.  At  one  place,  formerly  called  the  Morgan  Claim,  now  the 
Hope  Mine,  an  immense  amount  of  gold,  between  one  and  two  mil¬ 
lions,  it  is  said,  was  taken  out  within  a  small  space  several  years  ago. 
The  talcose  slates  in  places  along  on  the  hack  of  the  great  vein  have 
proved  very  rich,  paying  as  much  as  $80  a  ton.  Our  own  examination 
demonstrated  to  us  that  portions  of  this  rock  still  left  standing  contain 
a  large  amount  of  gold.  The  Enterprise  Mine  is  located  on  the  tal¬ 
cose  slate  belt,  which  lies  between  the  main  quartz  mass  and  a  very 
small  vein  parallel  with  it;  these  quartz  veins  sometimes  approach 
each  other  very  nearly ;  at  others,  they  are  widely  separated.  The  belt 
of  auriferous  slates  is  from  two  to  three  feet  in  thickness ;  its  yield  of 
gold  must  be  irregular,  or  it  would  he  worked  with  more  persistence. 

On  Albany  Hill,  explorations  and  attempts  at  mining  have  been 
made,  without  much  success.  The  north  side  of  the  hill  consists  of 

4 

*  It  is  not  certainly  known  which  of  the  tellurium  combinations  are  found  at  this  mine, 
as  they  have  not  yet  been  subjected  to  any  careful  analysis,  for  want  of  sufficient  mate¬ 
rial.  There  seems,  however,  to  be  two  combinations  present ;  Nagyagite,  or  telluride  of 
lead,  and  Sylvanite,  or  Graphic  Tellurium,  a  telluride  of  gold  and  silver. 


264 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


serpentine.  A  considerable  amount  of  copper  ore  is  seen  in  the  vari¬ 
ous  outcroppings  around  these  hills. 

Another  interesting  quartz-mining  locality  in  Calaveras  County  is  at 
and  near  West  Point,  about  sixteen  miles  east  of  Mokelumne  Hill. 
Here  are  a  great  number  of  quartz  veins,  all  in  granite,  having  a  course 
of  about  H.  50°  W.,  and  dipping  to  the  west.  Many  of  these  veins 
have  been  worked  by  Mexicans,  who  treat  the  quartz  with  arrastras, 
and  they  have  usually  done  a  good  business.  Hear  the  surface  the 
rock  is  very  soft,  and  requires  no  blasting  to  obtain  the  quartz ;  but  at 
a  depth  varying  from  thirty  to  ninety  feet,  it  becomes  hard,  so  that  the 
expense  of  mining  is  much  increased.  The  miners  have,  therefore, 
usually  abandoned  their  claims  when  water  was  reached,  and  betaken 
themselves  to  new  discoveries ;  but  there  is  reason  to  believe  that  in 
many  of  them  the  rich  quartz  is  far  from  exhausted. 

The  Mill  Vein,  discovered  in  1860,  bad  yielded  quartz  during  a  year 
from  its  discovery,  paying  $133  a  ton.  Its  width  was  from  three  inches 
to  one  foot.  The  Myers  &  Easton  Vein,  fourteen  to  twenty-four  inches 
wide,  is  similar  to  the  Mill  Vein,  and  had  yielded  very  well  on  the 
small  quantity  of  quartz  which  had  been  raised  when  visited  by  Mr. 
Ashburner,  in  1861.  The  Rathgeber  Vein  is  situated  three  miles  east 
of  West  Point,  runs  north  and  south,  and  dips  west  at  an  angle  of 
25°.  The  ore  from  this  vein,  near  the  surface  at  least,  was  very  rich; 
but  the  work  had  not  been  carried  to  a  sufficient  depth  when  visited 
to  enable  one  to  form  an  opinion  of  the  permanence  of  the  mine. 
There  were  three  mills  at  work  here,  in  1861.  These  were :  Jacobs 
&  Co.’s,  with  eight  stamps;  the  Woodhouse  Mill,  with  fifteen  stamps; 
and  Iverson’s  Mill,  with  eight  stamps. 

The  placer  and  hydraulic  mines  in  Calaveras  County  have  been  of 
great  importance,  but  are  now  much  fallen  off.  The  ordinary  river 
and  gulch  diggings  being  almost  entirely  exhausted,  and  not  differing 
in  any  essential  respect  from  those  existing  everywhere  in  the  Gold 
Region,  need  not  here  be  spoken  of.  The  surface  of  the  limestone  at 
Murphy’s  is  still  worked  to  a  considerable  extent,  a  very  long  and 
expensive  bed-rock  sluice  having  been  carried  up,  so  as  to  afford  fall 
enough  to  work  many  of  the  deeper  cavities  which  could  not  before 
be  reached. 


THE  WESTERN  SLOPE - CALAVERAS  COUNTY.  265 

The  principal  hydraulic  diggings  now  worked  are  in  connection  with 
the  volcanic  deposits,  and  these  are  very  widely  spread  over  this  region. 
On  the  southeastern  side  of  the  county,  parallel  with  the  Stanislaus, 
Table  Mountain  comes  down,  crossing  the  river  near  Abby’s  Ferry,  as 
before  described.  As  exposed  in  the  gap  through  which  the  road  from 
the  ferry  to  Murphy’s  passes,  there  appears  to  be  as  much  as  500  feet 
in  thickness  of  volcanic  and  sedimentary  material  resting  on  the  sur¬ 
face  of  the  limestone,  which  is  here  about  2200  feet  above  the  sea. 
The  upper  portion  is  basaltic  lava  about  150  feet  thick,  and  this  rests 
upon  a  series  of  beds,  about  350  feet  thick,  made  up  of  a  mixture  of 
sand  and  clay  with  volcanic  ashes  and  pumice,  containing  many  boul¬ 
ders  of  quartz  and  masses  of  silicified  wood.  These  rest  on  the  lime¬ 
stone,  which  has  the  same  deeply  eroded  surface  as  at  Sonora.  There 
are  many  prospecting  shafts  sunk  in  the  stratified  beds  which  lie  upon 
the  limestone;  but  none  of  them  seem  to  have  been  successful  in 
striking  at  this  point  a  channel  of  pay  gravel.  The  view  from  the 
summit  of  the  volcanic  ridge  above  Abby’s  Ferry  is  very  striking,  not 
only  from  its  picturesqueness,  but  from  the  excellent  opportunity  which 
it  affords  of  seeing  what  immense  changes  have  taken  place  in  the  topo¬ 
graphy  of  the  country  since  this  great  current  of  lava  flowed  down 
from  the  high  regions  of  the  Sierra.  The  town  of  Columbia  is  observed 
to  be  almost  exactly  on  the  same  level  as  the  surface  of  the  limestone 
on  the  north  side  of  the  river,  and  the  dark  mass  of  Table  Mountain  is 
seen  stretching  away  to  the  south,  evidently  the  continuation  of  the 
ridge  on  the  north  side,  while  between  these  two  parts  of  what  was 
once  one  continuous  flow  of  solid  lava  150  feet  in  thickness,  lies  the 
tremendous  canon  of  the  Stanislaus  fully  2000  feet  below,  with  steep, 
hare  walls,  between  which  there  is  hardly  more  than  room  for  the  river 
to  pass. 

How  large  a  portion  of  the  county,  in  a  northeasterly  direction  from 
Murphy’s,  is  covered  by  volcanic  overflows  cannot  be  ascertained  until 
a  detailed  survey  is  made  of  that  region ;  hut  it  is  evident  that  several 
great  lava  currents  swept  down  the  flanks  of  the  Sierra,  during  the 
period  of  volcanic  activity,  along  the  southeastern  side  of  the  county, 
as  the  deeply  eroded  outliers  of  erupted  matter  still  bear  witness. 

Between  Vallecito  and  Douglass  Flat,  on  the  south  side  of  the  road 


GEOL.  VOL.  I. — 34 


266 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


to  Murphy’s,  is  a  high  ridge  of  volcanic  breccia,  and  to  the  north  of 
this  is  an  immense  deposit  of  gravel  extensively  worked,  but  the  exact 
position  and  relations  of  which,  for  want  of  an  accurate  map  of  the 
reo-ion,  we  were  unable  to  determine.  A  deep  adit,  called  the  “  Mam- 
moth  Tunnel,”  is  being  driven  in,  to  drain  this  plateau  of  gravel.  It 
passes  through  a  tine-grained,  granitoid  rock,  composed  of  black  horn¬ 
blende  and  feldspar.  This  is  intersected  by  numerous  quartz  veins, 
which  are  very  variable  in  size  and  direction,  their  width  being  from  a 
few  inches  to  four  feet.  The  quartz  has  disseminated  through  it  copper 
pyrites  and  crystals  of  brown-spar. 

Another  extensive  region  of  volcanic  rocks  extends  from  the  north 
side  of  the  Big  Trees  west  towards  Railroad  Flat,  and  to  the  north  of 
Cave  City  ;  it  is  probably  with  this  that  the  volcanic  beds  in  the  vicinity 
of  Mokelumne  Hill  are  connected,  although  the  intermediate  region 
has  not  been  explored.  Portions  of  this  range  are  known  by  different 
names,  “  Table  Mountain”  being  one  of  them.  Railroad  Flat  is  quite 
surrounded  by  these  ridges,  which  rise  from  600  to  800  feet  above  the 
level  of  the  flat,  and  have  a  most  picturesque  effect.  One,  which  from 
its  fancied  resemblance  to  a  fortress  has  been  called  Fort  Hill,  is  shown 
in  the  annexed  wood-cut  (Fig.  40).  Its  outline  contrasts  sharply  with 
the  rounded  contour  of  the  granitic  rocks  of  Blue  Mountain  seen  in 
the  distance.  There  were  no  washings  or  mining  going  on  in  this 
vicinity  when  visited,  in  the  autumn  of  1863. 

The  district  of  Mokelumne  Hill  and  its  vicinity  has  been  noted  for 
the  extreme  richness  of  its  auriferous  deposits  under  the  volcanic  beds. 
Those  in  the  immediate  neighborhood  of  the  Hill  are  pretty  much  ex¬ 
hausted  ;  but  others  about  four  miles  south,  at  a  place  known  as  Chili 
Gulch,  are  still  productive  and  actively  worked.  The  bed-rock  here 
is  quite  varied  in  character.  Around  French  Hill,  a  little  to  the  north 
of  the  town,  silicious  and  micaceous  slates  are  seen,  overlain  by  beds  of 
compact  argillaceous  sandstones ;  the  dip  of  the  metamorphic  strata  is 
to  the  northeast  at  an  angle  of  45°.  Hornblende-rock  also  occurs  in 
large  masses,  and  seems  to  pass  into  a  kind  of  granite. 

The  sedimentary  and  volcanic  deposits  near  the  town  are  about  250 
feet  thick  and  rest  on  the  bed-rock,  which  has  an  elevation  of  about 
1800  feet  above  the  bed  of  the  Mokelumne  River,  which  is  only  a  mile 


THE  WESTERN  SLOPE  —  CALAVERAS  COUNTY. 


2G7 


distant  to  the  north.  The  upper  part  of  the  volcanic  ridge  is  a  mass 
of  boulders  or  fragments  of  trachytic  lava,  not  polished  or  smooth,  hut 


Fig.  40. 


FORT  HILL,  NEAR  RAILROAD  FLAT. 


roughly  rounded,  as  if  by  friction  with  each  other,  unaided  by  water. 
These  boulders  are  largest  at  the  top  and  grow  quite  small  towards  the 
bottom  of  the  bed,  which  is  here  about  fifty  feet  thick.  There  are  no 
other  kinds  of  rock  than  volcanic  represented  in  this  bed,  and  no  stray 
pebbles,  even  of  quartz  or  slate ;  this  fact  is  not  peculiar  to  the  lava  ridges 
of  Mokelumne  Hill,  but  has  been  observed  in  many  other  places  in  this 
region.  To  account  for  the  formation  of  such  deposits  is  not  easy.  It 
can  hardly  be  the  result  *of  the  disintegration  of  the  lava  by  ordinary 
decomposition ;  nor  is  it  possible  to  suppose  that  currents  ot  water  have 
brought  the  lava  boulders  together,  as  gravel  is  ordinarily  accumulated; 
for  how,  in  this  case,  could  it  be  explained  why  the  largest  masses  are 
on  the  top,  and  that  no  fragments  of  other  rocks  have  become  mixed 
with  the  trachytic  materials?  It  would  seem  as  if  the  mass  of  lava 
must  have  been  broken  up,  while  flowing  and  before  it  was  entirely 
consolidated,  and  that  the  fragments  were  pushed  over  each  other  by 
the  pressure  of  the  mass  from  behind ;  under  such  circumstances,  the 
lower  portions,  having  to  undergo  the  greatest  amount  of  pressure  and 
motion,  would  necessarily  be  broken  up  more  completely  than  the 
upper,  and  the  whole  would  thus  present  the  appearance  it  now  does, 


2G8 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


which  is  that  of  a  mass  of  fragments  of  rock  rounded  by  friction  with 
each  other,  but  not  sorted  by  currents  of  water.  Something  of  the 
same  appearance  lias  been  observed  by  us  in  the  beds  of  ancient  vol¬ 
canic  materials,  intercalated  among  the  sandstones  of  Lake  Superior. 

Beneath  this  bed  of  lava  boulders,  is  a  mass  of  strata,  in  some  places 
nearly  two  hundred  feet  thick,  consisting  chiefly  of  volcanic  ashes, 
stratified  and  consolidated  by  water,  resembling  the  beds  seen  under 
the  lava,  in  so  many  localities  in  the  Sierra.  These  sedimentary  vol¬ 
canic  strata  are  often  fine-grained  and  homogeneous,  having  a  light 
pinkish-red  color,  and  breaking  with  a  conch oidal  fracture.  The  upper 
beds  have  much  pumice  mixed  with  them.  Immediately  on  the  bed¬ 
rock  lies  the  stratum  of  pay-gravel,  which  in  some  places  has  been  of 
the  most  astonishing  richness,  but  is  now  entirely  worked  out,  having 
occupied  only  a  very  small  area. 

The  Mokelumne  Hill  channel  of  auriferous  gravel  seems  to  be  con¬ 
tinued  in  that  of  Chili  Gulch,  which  lies  to  the  south,  and  where  ex¬ 
ploration  was  actively  going  on  from  1860  to  1864.  The  position  of 
this  channel  is  about  150  feet  lower  than  that  of*  Mokelumne  Hill. 
There  are  several  beds  of  gravel  here  in  the  lava ;  but  the  pay-dirt  is 
at  the  bottom  and  forms  a  stratum  about  eight  feet  thick.  Much  of  it 
is  so  compacted  together  that  it  has  to  be  stamped  before  it  can  be 
washed.  An  interesting  specimen  of  a  part  of  the  head  of  a  rhinoceros 
was  found  here,  and  it  is  the  first  and  only  instance,  so  far  as  we  know, 
of  the  discovery  of  this  animal  west  of  the  Bocky  Mountains.  The  spe¬ 
cies  is  considered  by  Dr.  Leidy,  to  whom  it  was  referred  for  examina¬ 
tion,  to  be  new,  and  it  was  called  by  him  Rhinoceros  hesperius ,  and  will 
be  found  described  in  the  Proceedings  of  the  Academy  of  Natural  Sci¬ 
ences  of  Philadelphia,  for  the  year  1865.  The  specimen  consists  of  the 
right  branch  of  the  lower  jaw,  including  the  symphysial  portion  of 
both  sides,  with  the  left  condyle.  It  is  completely  fossilized,  and 
closely  resembles  in  general  appearance  the  fossils  of  the  Mauvaises 
Terres,  in  Nebraska. 


TIIE  WESTERN  SLOPE - AMADOR  COUNTY. 


2G9 


^Section  VI. — Amador  County. 

Amador  County  lies  between  the  Cosunmes  and  the  Mokelumne 
Rivers,  and  is  considerably  smaller  than  most  of  the  mining  counties 
north  and  south  of  it.  The  belt  of  auriferous  rocks  runs  directly  through 
its  centre,  the  principal  mining  towns  being  Jackson,  Sutter,  Ajnador, 
and  Drytown,  and  it  occupies  a  width  of  about  twelve  miles.  The  pro¬ 
ductive  portion  of  this  -belt  is,  however,  chiefly  along  its  northeastern 
side.  Ordinary  gulch  and  river  mining  has  been  extensively  carried 
on  here ;  but  is  now  almost  entirely  discontinued.  The  quartz  mines, 
however,  have  been,  and  still  are,  of  great  importance.  The  belt  of 
limestone,  noticed  as  so  conspicuous  in  Tuolumne  and  Calaveras,  ex¬ 
tends  as  far  as  Volcano;  three  or  four  miles  beyond  it,  to  the  north¬ 
east,  we  strike  the  granite,  which  is  continuous  up  into  the  High  Sierra. 
The  volcanic  formations  are  principally  developed  along  the  southern 
side  of  the  county,  near  the  Mokelumne  River,  and  especially  in  the 
vicinity  of  Jackson;  the  northwestern  portion  is  occupied  by  the  aurif¬ 
erous  slates  and  has  little  of  peculiar  geological  interest. 

Coming  into  the  county  from  the  side  of  Sacramento,  lone  Valley 
was  the  first  locality  examined.  Immediately  north  of  lone  City,  hard, 
blue  metamorphic  slates  are  seen,  running  H.  20°  to  25°  TV,  and  dipping 
east  at  an  angle  of  67°.  Farther  east  the  slates  are  seen,  very  little 
altered  from  their  original  condition;  their  color  is  light-gray  at  the  sur¬ 
face,  and  dark  bluish-black  at  a  little  distance  beneath.  The  town  is  sur- 
rounded  on  the  south,  southeast,  and  southwest  by  low  terrace-like  hills, 
with  flat  tops,  which  are  the  remains  of  a  late  Tertiary  formation  with 
which  this  region  was  once  extensively  covered  ;  but  which  is  now  very 
irregularly  worn  away,  leaving  outliers  far  out  into  the  Sacramento 
plain.  One  of  these  outliers,  four  or  five  miles  west  of  lone,  and  called 
Pratt’s  Hill,  was  ascended  by  Mr.  ROnond,  who  found  it  to  be  distinctly 
stratified  and  chiefly  made  up  of  alternating  deposits  of  clay  and  gravel, 
with  a  bed  of  trachyte  at  the  top.  The  gravel  is  composed  exclusively 
of  large  pebbles  of  volcanic  origin.  The  clays  are  of  various  colors, — 
white,  red,  and  purple  ;  of  the  white,  a  good  deal  has  been  sold  and  used 
for  paint.  These  strata  are  superior  in  position  to  the  sandstones  imme- 


270 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


diately  about  lone,  which  latter  are  divided  into  two  portions;  the  lower 
of  these  is  made  up  of  a  series  of  white,  pink,  and  red  sandstones,  while 
the  upper  is  a  highly  ferruginous  rock,  and  is  about  twenty  feet  thick. 
This  member  of  the  formation  contains  so  much  iron  in  places  as  to 
become  a  tolerable  ore;  in  other  localities  it  forms  a  quartzose  breccia, 
cemented  by  brown  oxide  of  iron.  It  is  quarried  to  some  extent  for 
walls  #nd  fences.  Where  these  rocks  occupy  the  surface,  they  are 
covered  thickly  with  chamisal,  while  the  metamorphic  slates  ot  the 
vicinity  support  a  scattered  growth  of  line  oak  trees,  with  a  few  pines 
on  the  slopes. 

The  lower  division  of  the  sandstones  is  of  especial  interest  as  contain¬ 
ing  a  bed  of  lignite,  or  imperfect  coal,  which  has  been  worked  to  some 
extent.  The  locality  is  about  two  miles  south  of  lone,  near  the  Stock- 
ton  road.  This  coal  is  associated  with  beds  of  white  clay.  A  drift 
was  run  in,  by  Mr.  Hall,  the  proprietor  of  the  mine,  for  a  distance  of 
live  hundred  feet,  in  which  a  good  section  of  the  rocks  connected  with 
the  coal  was  obtained;  but  it  was  not  accessible  at  the  time  of  our  visit. 
From  Mr.  Hall  we  learned,  however,  that  the  upper  stratum  exposed 
was  a  white,  somewhat  argillaceous  sandstone,  containing  a  large  num¬ 
ber  of  fossil  leaves,  in  a  good  state  of  preservation,  one  of  which  was 
eight  inches  long ;  unfortunately  these  had  not  been  preserved.  Below 
this,  was  a  bed  of  white  clay,  with  traces  of  vegetable  matter ;  under 
this  a  seam  of  bituminous  shale,  one  foot  thick,  succeeded  by  a  bed  of 
sandstone,  with  a  thin  layer  of  coal  at  the  bottom,  then  a  bed  of  clay, 
under  which  was  the  coal  stratum,  seven  feet  thick  in  its  maximum 
development.  Below  the  coal  is  a  bed  of  sandstone,  which  has  not 
been  penetrated  to  the  bottom. 

The  coal  evidently  occupies  a  small  basin-like  depression  in  the 
strata,  and  is  made  up  of  a  mass  of  vegetable  matter  brought  together 
and  imperfectly  carbonized.  It  is  of  the  same  age  as  the  lignite  seams 
of  the  auriferous  gravels  under  the  basaltic  lava,  namely,  later  Plio¬ 
cene.  It  is  of  a  brownish-black  color,  without  lustre,  and  soon  crum¬ 
bles  to  pieces  when  exposed  to  the  air.  The  upper  part  of  the  bed  is 
something  half  way  between  peat  and  lignite ;  the  lower,  a  denser  ma¬ 
terial,  brittle  as  resin,  and  burning  with  a  hot  and  smoky  flame.  This 
material  is  used  by  Mr.  Hall  for  running  a  steam  flour-mill,  and  answers 


T1IE  WESTERN  SLOPE - AMADOR  COUNTY. 


271 


the  purpose  very  well ;  some  of  it  lias  been  shipped  to  Sacramento  for 
sale,  but  it  is  too  crumbly  to  bear  transportation.  The  whole  region 
about  lone  has  been  prospected  for  coal,  but  without  success.  At 
Buckeye  Valley,  about  five  miles  northeast  of  lone,  on  the  road  to 
Sacramento,  coal,  or  lignite,  has  been  found  in  several  small  indepen¬ 
dent  basins ;  but  these  deposits  were  not  accessible  at  the  time  of  our 
# visit.  They  are  undoubtedly  of  the  same  age  as  that  at  lone,  and 
probably  of  much  the  same  character.  Fragments  of  the  Tertiary 
extend  all  along  the  foot-hills  of  the  Sierra  in  this  region,  and  wherever 
they  occur  coal  is  likely  to  be  found ;  but  these  deposits  cannot  be 
expected  to  be  of  value  except  for  local  consumption,  there  being  no 
reason  to  suppose  that  they  occur  in  continuous  arid  extensive  beds. 
Besides,  the  material  is  not  sufficiently  consolidated  to  bear  much 
transportation. 

Between  Jackson  and  Drytown,  in  a  line  about  eight  miles  long, 
running  nearly  northwest  from  the  first-named  place,  is  a  belt  of  quartz 
mines,  which  have  been  and  still  are  worked  with  great  activity, 
and  are  among  the  most  important  in  the  State.  The  outcrops  of 
quartz  on  which  these  mines  are  situated,  are  in  a  line  with  the  great 
quartz  vein  of  Mariposa,  Tuolumne,  and  Calaveras  Counties,  as  already 
noticed,  and  this  seems  to  be  the  extreme  northern  point  to  which  it 
can  be  traced.  It  is  not,  by  any  means,  a  continuous  bed  or  vein  of 
quartz ;  but,  rather,  a  series  of  nearly  parallel  belts,  or  lenticular 
masses,  with  long  barren  intervals  between  thenq  but  yet  arranged 
pretty  nearly  in  the  same  course,  so  that  a  straight  line  drawn  in  a 
direction  of  II.  27°  W.  from  Jackson  would  either  cut  or  pass  very 
near  the  whole  of  them. 

The  mine  as  well  as  the  mills  on  this  belt  were  examined,  pretty 
carefully,  by  Mr.  Ashburner,  in  1861,  and  since  that  time  have  been 
occasionally  visited  by  others  of  the  Survey.  The  following  statement 
of  their  condition  refers  to  the  year  1861,  where  a  later  date  is  not  par¬ 
ticularly  specified.  ✓ 

The  Oneida  Mine  and  Mill  are  situated  about  two  miles  northwest 
of  Jackson.  The  mill  is  one  of  sixteen  stamps,  run  by  steam,  and  ca¬ 
pable  of  treating  about  400  tons  of  rock  per  month.  The  vein  is  in 
slate,  and  dips  to  the  east  at  an  angle  of  64°;  its  average  width  is  eight 


« 


272 


GEOLOGY  OF  TllE  SIERRA  NEVADA. 


feet,  and  the  rock  pays  from  $10  to  $11  per  ton.  At  the  depth  below 
the  surface  of  185  feet  perpendicular,  or  260  feet  on  the  incline,  the 
yield  of  the  quartz  was  said  to  he  as  good  as  in  any  part  of  the  mine. 

The  Eureka  and  Badger  Mines  are  owned  by  Messrs.*  Hay  ward  & 
Chamberlain,  and  have  been  worked  for  about  ten  years.  Their  daily 
production  -was,  in  1861,  about  100  tons.  The  vein  is  inclosed  in  a 
dark-colored,  rather  soft  argillaceous  slate;  it  has  a  strike  of  U.  22°  W.,  . 
xmd  dips  to  the  east  at  an  angle  of  70°.  The  foot-wall  is  soft  and 
very  friable,  while  the  hanging-wall  is  harder  and  more  decidedly  meta- 
morphic.  The  Eureka  and  the  Badger  were  formerly  two  separate 

• 

concerns ;  but  are  now  worked  together,  the  rock  from  the  Eureka 
being  treated  at  the  mill  of  the  same  name,  while  that  from  the  other 
mine  goes  to  the  Upper  and  Lower  Badger  Mills.  In  the  Eureka,  the 
mass  of  veinstone  is  from  eight  to  twenty  feet  wide;  but  in  the  Badger 
it  widens  out  suddenly  to  forty  feet.  The  length  of  ground  worked,  in 
both  mines,  is  about  470  feet;  to  the  south  of  the  Badger  Shaft,  which 
is  on  the  south  end  of  the  mine,  there  is  hardly  any  quartz  to  be  seen, 
and  the  lode,  which  is  eight  feet  wide  on  the  north  side  of  the  Eureka, 
pinches  out  very  rapidly  in  that  direction,  so  that  the  body  of  quartz 
worked  is  very  short  in  proportion  to  its  great  width,  being  almost 
a  column,  or  chimney,  rather  than  a  vein.  At  the  junction  of  the  two 
mines  there  is  a  large  mass  of  slate  and  soft  clay,  mixed  with  a  little 
quartz,  which  is  often  in  a  state  of  fine  powder,  owing  to  the  pressure 
of  the  yielding  foot-wall.  This  pressure  is  so  great,  that  the  timbers, 
which  are  sometimes  two  feet  in  diameter,  are  in  a  short  time  twisted 
and  bent  like  reeds,  and  have  to  be  replaced  by  new  ones.  The  depth 
to  which  this  mine  had  been  worked,  in  1861,  was  500  feet  on  the  in¬ 
cline,  equal  to  470  in  a  vertical  descent;  in  1863  the  principal  shaft  was 
650  feet  deep,  and  the  lowest  level  had  then  been  extended  on  the  vein 
for  a  distance  of  560  feet.*  The  quartz  is  of  a  grayish-white  color, 
and  interlaminated  with  seams  of  soft  slate,  which  have, a  direction 
parallel  to  the  walls  of  the  vein.  The  gold  is  very  regularly  and  uni- 


*  This  shaft  is  stated  in  a  newspaper  of  the  vicinity  (the  Jackson  Ledger)  to  be,  in 
June,  1865,  920  feet  deep.  If  so,  it  is,  next  to  the  Cliff  Mine,  on  Lake  Superior,  the 
deepest  shaft  in  the  United  States. 


THE  WESTERN  SLOPE - AMADOR  COUNTY.  273 

formly  diffused  through  the  mass  of  veinstones,  and  is  rarely  in  parti¬ 
cles  large  enough  to  he  visible  to  the  eye.  There  is  about  two  or  three 
per  cent,  of  pyrites  in  the  veinstone,  which  was,  in  1861,  allowed  to 
run  to  waste. 

The  Eureka  Mill  has  forty  stamps,  and  is  run  by  water  during  the 
wet  season,  and  by  steam  in  the  summer.  About  sixty  tons  of  quartz 
from  the  Eureka  Mine  were  daily  worked  at  this  mill,  in  1861,  and 
yielded  $10.25  per  ton:  the  expense  of  the  treatment  in  the  mill 
(stamping  and  amalgamating)  being  only  $1.32  per  ton.  The  cost  of 
the  extraction  of  the  quartz  from  the  mine,  at  that  time,  was  estimated 
at  $2.50  per  ton,  leaving,  as  wilt  be  seen,  a  handsome  margin  for  pro¬ 
fit.  Indeed  few,  if  any,  mines  in  the  State  have  been  more  uniformly 
and  permanently  successful,  while  the  yield  of  gold  to  the  ton  of  rock 
stamped  is  quite  low. 

The  Upper  Badger  Mill  has  sixteen  stamps  and  is  run  by  water.  As 
the  quartz  from  the  Badger  Mine  has  a  good  deal  of  slate  mixed  with  it, 
it  is  worked  in  this  mill  at  the  rate  of  two  tons  per  day  for  each  stamp, 
the  whole  cost  of  stamping  and  amalgamating  at  this  mill  is  exceed¬ 
ingly  low,  namely,  $0.66  to  $0.67  per  ton,  when  all  the  conditions  are 
favorable,  and  water  sufficient ;  this  is  a  lower  figure  for  the  treatment 
of  the  quartz  than  any  other  mill  in  the  State  can  show.  The  Lower 
Badger  Mill  has  twelve  stamps,  and  can  run  through  twenty  tons  a  day 
of  the  soft  slaty  quartz  from  the  mine  of  the  same  name.  As  at  the 
last-mentioned  mill,  the  stamps  are  run  at  a  veiy  rapid  rate,  namely, 
eighty  blows  per  minute.  The  yield  of  the  quartz  at  these  mills  is 
about  the  same  as  at  the  Eureka.  The  quartz  at  the  Eureka  and  Badger 
Mines  did  not  begin  to  pay  well  until  a  considerable  depth  had  been 
reached  (100  feet,  it  is  said) ;  but  since  that,  its  tenor  in  gold,  at  least 
up  to  1863,  has  been  remarkably  uniform. 

The  “  Ilerbertville  Quartz  Mining  Company,”  were,  in  1861,  work¬ 
ing  a  mine  near  Amador,  on  another  of  those  chimneys  of  quartz 
which  characterize  this  region.  The  ground  worked  was  only  200 
feet  long,  and  the  depth  reached  in  the  western  shaft  was  640  feet  on 
the  incline,  and  524  vertical.  Its  bearing  is  U.  85°  W.,  and  its  dip  to 
the  south,  at  an  angle  of  55°.  The  vein  was  eighteen  inches  wide  on 
the  surface,  and  it  expanded  gradually,  until  a  depth  of  400  feet  was 


OEOL.  VOL.  T. — 3") 


274 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


reached,  where  its  width  was  four  feet;  below  that,  it  became  pinched 
and  the  quartz  grew  poorer,  its  yield  of  gold  having  been  greatest  at 
200  feet  from  the  surface. 

The  mill,  which  had  thirty  stamps,  and  was  run  by  steam,  was  stamp¬ 
ing  dry,  in  1861,  and  working  over  old  tailings,  which  yielded  $20  per 
ton.  The  expense  of  the  treatment  was  $4.59  per  ton. 

The  “  Amador  Quartz  Mining  Company”  had,  in  1861,  a  twenty- 
stamp  mill,  run  by  steam,  and  treating  rock  from  a  vein  in  the  vicinity, 
which  has  a  strike  of  N.  40°  W.,  and  dips  to  the  east  at  an  angle  of  57°. 
The  shaft  was  down  450  feet,  on  the  incline,  which  is  equal  to  a  per¬ 
pendicular  depth  of  377  feet.  The  vein  varies  in  width  from  eight  to 
twenty-four  feet,  averaging  twelve  probably.  At  the  bottom  of  the 
shaft  it  was  eight  feet  thick,  and  had  been  drifted  on  fifty  feet  to  the 
north.  The  quartz  was  in  many  places  exceedingly  soft,  and  easily 
broken,  having  apparently  been  subjected  to  immense  pressure,  from  the 
movements  of  the  inclosing  rock.  The  hanging-wall  is  of  soft,  black 
slate;  the  foot-wall  of  hard  metamorphic  rock.  As  is  the  case  in  most 
of  the  mines  in  this  vicinity,  the  workings  are  chiefly  in  depth ;  the 
greatest  amount  drifted,  to  the  north  of  the  shaft,  being  120  feet,  at  a 
depth  of  302  feet,  and  to  the  south  only  fifty  feet.  The  yield  of  the 
quartz  was  about  $10  a  ton,  and  the  mill  could  crush  thirty  tons  per 
day,  at  an  expense  of  $1.79  per  ton. 

The  Spring  Hill  Mills,  on  Amador  Creek,  are  two  in  number,  one 
with  fifteen,  the  other  with  sixteen  stamps;  these  were  employed,  in 
1861,  in  working  the  quartz  from  a  vein  so  near,  that  the  rock  could  be 
dumped  from  the  mouth  of  the  shaft  directly  on  to  the  spalling-ground. 
The  direction  of  the  vein  is  N.  22°  W.,  and  it  dips  to  the  east  at  an 
angle  of  55°  to  60°.  The  shaft  was  sunk  to  the  depth  of  150  feet  on 
the  incline,  or  126  feet  perpendicular.  The  extreme  length  of  the 
workings  was  about  900  feet,  and  the  average  width  of  the  vein  about 
eighteen  inches.  Near  the  bottom  of  the  shaft,  and  a  little  to  the  south 
of  it,  there  was  a  sudden  expanding  of  the  vein  to  a  width  of  twenty 
feet,  which  it  maintained  for  a  length  of  150  and  a  depth  of  40  feet. 
In  many  places  the  lode  entirely  disappears  and  is  replaced  by  a  very 
soft,  black  shale,  containing  small  quantities  of  quartz  in  fine  powder. 
The  yield  of  the  quartz  of  this  vein  was  about  $10  a  ton,  and  the  cost 


THE  WESTERN  SLOPE  —  AMADOR  COUNTY. 


275 


of  treatment  in  the  mill  $1.63  per  ton ;  that  of  extraction  from  the 
mine  was  estimated  at  $2  per  ton. 

The  names  of  both  the  mills  and  the  mines,  and  also  the  character 
and  extent  of  the  workings,  have  changed  somewhat  since  1861 ;  but 
the  facts  given  above  are  of  interest,  as  showing  the  general  character 
of  the  quartz-mining  operations  in  this  vicinity.  Their  present  condi¬ 
tion  and  future  development,  up  to  the  time  of  publication  of  the  volume 
more  especially  devoted  to  Economical  Geology,  will  be  found  in  that 
part  of  the  Report. 

There  is  quite  an  important  mining  district  at  Volcano,  about  sixteen 
miles  east  of  Jackson.  On  the  road  between  these  two  places,  Mr. 
Rdmond  observed  granitic  and  feldspathic  rocks,  which  were  first  seen 
about  five  miles  from  Jackson.  At  Volcano,  we  are  on  the  great  lime¬ 
stone  belt  of  the  Sierra,  which  here  has  a  north-northwest  direction, 
and  almost  a  vertical  dip ;  as  at  other  places,  it  is  cut  by  heavy  trap- 
dykes.  The  formation  at  this  place  closely  resembles  that  at  Sonora, 
being  a  white  saccharoidal  marble,  with  shades  and  markings  of  blue, 
sometimes  largely-crystalline,  but,  in  places,  quite  fine-grained.  Its  sur¬ 
face  had  been  extensively  eroded  previous  to  the  deposition  of  the  aurif¬ 
erous  gravel  upon  it,  presenting  the  same  appearance  which  has  been 
already  noticed  in  describing  the  limestone  belt  of  Tuolumne  County, 
and,  like  that,  having  the  deep  and  curiously  eroded  cavities  filled  with 
rich  auriferous  detritus.  At  Indian  Gulch,  near  Volcano,  there  are 
small  quartz  veins  in  this  formation.  Hear  the  contact  of  the  slates 
with  the  limestone,  the  latter  acquires  a  slaty  character.  There  are 
also  many  layers  of  flint,  or  chert,  which  are  most  abundant  along  the 
line  of  division  between  the  crystalline  marble  and  the  slaty  beds  of 
the  same  rock. 

At  the  time  of  Mr.  Ashburner’s  visit  to  this  district,  in  1861,  there 
were  three  principal  veins  of  auriferous  quartz  worked,  and  the  pros¬ 
pects  of  this  branch  of  the  mining  business  were  quite  flattering.  The 
Whitman  Vein  is  about  one  mile  east  of  Volcano,  and  occurs  in  a  band 
of  slate  which  lies  between  two  masses  of  granite.  It  has  been  traced 
for  more  than  two  miles,  and  has  a  general  trend  of  H.  25°  E.,  and 
dips  to  the  west  at  an  angle  of  65°  ;  this  direction  and  dip  arc,  as  will 
be  noticed,  quite  exceptional.  The  width  of  the  vein  varies  from  a  few 


276 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


inches  to  ten  feet,  but  averages  about  six  feet.  The  Italian’s  Vein  is 
in  the  same  belt  of  slate  as  the  Whitman ;  its  direction  is  about  27. 
40°  E.,  and  it  dips  to  the  east  at  an  angle  of  45°.  Its  width  is  from 
four  to  five  feet.  The  Leviathan  Vein  is  on  the  same  range  as  the  two 
others  noticed  above.  It  bears  17.  30°  E.,  and  dips  east  at  a  varying 
angle;  its  width  is  from  nine  to  twenty-five  feet.  The  yield  of  gold, 
in  this  vein,  was  quite  high  near  the  surface,  and,  at  the  depth  of  sev¬ 
enty-five  feet,  when  examined  by  Mr.  Ashburner,  it  was  still  very  good, 
although  variable,  running  from  $10  to  $70  per  ton.  There  was  only 
one  mill,  that  of  Rouse  &  Co.,  in  operation  in  1861.  It  was  a  small 
concern  of  only  five  stamps,  run  by  steam,  and  doing  custom-work 
exclusively,  for  which  $5  per  ton  was  charged. 

There  was,  in  1861,  a  quartz  lode  on  the  north  fork  of  the  Mokel- 
umne  River,  about  six  miles  east  of  Volcano,  called  the  Mountain 
Quartz  Vein,  and  a  mill  of  the  same  name.  The  district  is  a  continu¬ 
ation  of  that  of  West  Point,  and  the  vein  is  similar  in  character  to 
those  on  the  other  side  of  the  river.  This  lode  is  inclosed  in  granite, 
and  runs  about  17.  25°  W.,  dipping  to  the  east;  it  was  about  three  feet 
wide  at  a  depth  of  100  feet.  The  quartz  contains  a  large  amount  of 
pyrites  and  a  little  galena.  The  mill  had  four  stamps,  with  two  arrastras, 
and  the  yield  of  gold  was  stated  at  $100  per  ton.  Of  the  development 
of  the  Volcano  quartz  mines  since  1861,  we  have  no  information. 

In  the  vicinity  of  Volcano,  the  detrital  formation  resting  on  the  aurif¬ 
erous  slates  is  quite  thick,  and  in  many  places  has  been  extensively 
worked  for  gold.  Two  small  diamonds  were  shown  Mr.  Remond  as 
having  been  obtained  from  the  washings  here,  and  the  circumstances 
were  such  as  to  warrant  the  belief  that  the  discovery  was  a  bond  fide 
one.  The  crystals  were  small,  having  the  form  of  an  icositetrahedron, 
and  their  faces  were  curved  in  the  manner  so  peculiar  to  this  gem. 
The  auriferous  gravel  is  overlain,  as  at  Mokelumne  Hill,  by  horizontal 
beds  of  white  and  pink  volcanic  materials,  consisting  chiefly  of  ashes 
and  pumice  cemented  and  stratified  by  water.  Upon  these  is  a  mass  of 
trachyte,  broken  into  rounded  fragments  on  the  surface.  A  consider¬ 
able  number  of  bones  and  teeth  of  the  mastodon  and  other  animals 
have  been  found  in  the  auriferous  gravels  near  Volcano. 

In  one  of  the  detrital  beds  in  this  vicinity,  a  distinctly  marked  quartz 


THE  WESTERN  SLOTE - AMADOR  COUNTY. 


277 


vein  was  observed,  cutting  through  the  gravel,  and  evidently  formed 
since  its  deposition  by  the  action  of  waters  holding  silica  in  solution. 
The  mass  of  the  vein  was  of  agate  and  chalcedony ;  but  portions  were 
of  a  ferruginous  character.  This  is  not  by  any  means  an  isolated  case; 
other  localities  have  been  noticed,  where  all  the  conditions  necessary 
to  the  formation  of  quartz  veins,  similar  in  their  general  features  to 
those  in  the  auriferous  slates,  must  have  existed  during  the  most  recent 
geological  epoch. 

These  masses  of  volcanic  materials  which  play  so  important  a  part 
between  Volcano,  Jackson,  and  Mokelumne  Hill,  are  connected  with 
the  great  volcanic  table,  or  lava  flow,  which  extends  up  on  the  ridge 
between  the  Cosumnes  and  the  Mokelumne  Iiivers  ;  over  this  the 
road  from  Volcano  across  the  Sierra  passes  for  a  distance  of  about 
thirty-five  miles.  The  deep  valley  of  the  Cosumnes  runs  nearly  parallel 
with  this  road  for  many  miles,  exhibiting  a  fine  section  of  the  sedimen¬ 
tary-volcanic  and  basaltic  rocks.  The  same  is  the  case  with  the  Mokel¬ 
umne  River  on  the  south,  the  channels  of  these  rivers  seeming  to  have 
both  been  entirely  cut  down  in  the  volcanic  masses  since  these  were 
erupted. 

The  vicinity  of  Jackson  affords  an  excellent  opportunity  for  examin¬ 
ing  the  lavas  and  the  underlying  beds  of  ashes  and  gravel.  The  town 
and  the  adjacent  region  are  underlain  by  the  auriferous  slates ;  but 
ridges  of  volcanic  materials  have  been  formed  by  the  unequal  denuda¬ 
tion  of  the  great  mass  of  eruptive  matter  which  seems  to  have  covered 
an  extensive  area  in  former  times ;  but  which  has  now  disappeared,  with 
the  exception  of  these  few  outliers,  which  form  plateaux  or  low  table 
mountains,  of  no  very  regular  forms,  partly  surrounding  the  town. 
We  have  here,  as  at  Mokelumne  Hill,  a  mass  of  rounded  trachytic  peb¬ 
bles,  or  boulders,  covering  the  tops  of  the  ridges.  This  may  be  well 
seen  on  the  edge  of  the  plateau  about  three  miles  north  of  the  town, 
where  the  stratum  of  rolled  fragments  of  trachyte  is  not  less  than  fifty 
feet  thick,  and  covers  a  deposit  of  sedimentary-volcanic  beds  at  least 
250  feet  in  thickness. 

The  Jackson  Butte  is  a  very  conspicuous  outlier  of  the  volcanic  for¬ 
mation  so  extensively  developed  in  this  region,  and  it  is  often  ascended 
for  the  sake  of  the  fine  view  of  the  surrounding  country  which  can  be 


278 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


had  from  its  summit.  It  was  not  measured ;  hut  was  estimated  to  he 
1200  feet  above  the  town  of  Jackson,  and  800  feet  above  the  ground  at 
its  base.  The  excavations  made  by  prospecters  around  the  Butte  show 
that  it  rests  on  horizontal  strata  of  the  usual  tine  clays,  stratified  ashes, 
and  pumice;  but  the  upper  600  feet  of  the  hill,  which  has  an  irregular, 
conical  shape,  is  made  up  of  beds  of  lava,  of  a  reddish  color,  and  very 
distinctly  stratified.  These  beds  are  not  horizontal,  but  inclined  at  an 
angle  of  from  50°  to  60°,  the  dip  being  in  almost  every  direction,  but 
chiefly  either  to  the  northeast  or  the  southwest.  It  is  possible,  perhaps 
probable,  that  this  was  an  independent  volcanic  vent,  and  that  the  in¬ 
clined  position  of  the  beds  of  lava,  of  which  it  is  made  up,  is  due  to 
their  accumulation  on  the  steep  slopes  of  the  crater.  The  instances  are 
very  few,  however,  in  which  an  eruptive  mass  of  lava  can  be  seen  to 
have  made  its  way  upwards  through  the  slates ;  in  such  cases  the  form 
which  is  usually  exhibited  is  that  of  a  dyke,  rather  than  that  of  matter 
coming  from  a  crater-like  orifice. 

A  very  large  amount  of  prospecting  for  copper  has  been  done  in 
Amador  County,  and  many  shafts  sunk,  from  some  of  which  a  con¬ 
siderable  quantity  of  ore  was  taken  in  1862  and  1863.  The  princi¬ 
pal  field  of  these  explorations  was  along  a  line  which  appeared  to  be 
the  continuation  of  the  great  cupriferous  belt  of  Calaveras  County, 
already  noticed  as  extending  through  from  Copperopolis  to  Campo 
Seco.  One  of  the  principal  mines  is  that  of  Dr.  Hewton,  about  four 
miles  west  of  lone  City ;  from  this  a  considerable  amount  of  good  ore 
is  said  to  have  been  shipped.  Of  their  present  importance  and  proba¬ 
ble  permanent  value  we  have,  however,  no  accurate  information,  as  no 
detailed  surveys  have  been  made  by  us  in  that  region. 

There  is  also  another  cupriferous  belt,  some  miles  to  the  northeast  of 
the  one  already  noticed,  and  in  the  vicinity  of  Fiddletown.  Indications 
of  copper  ores  are  frequent  through  that  region ;  but  no  large  deposits 
had  been  developed  at  the  time  we  passed  through  that  district,  in 
1863.  Here,  as  well  as  elsewhere  in  the  State,  the  high  price  of  labor 
and  fuel,  the  scarcity  of  water  and  the  distance  from  a  market  operate 
to  retard  the  development  of  metalliferous  deposits,  which,  under  more 
favorable  conditions,  would  be  of  great  value. 


TIIE  WESTERN  SLOPE - EL  DORADO  COUNTY. 


270 


Section  VII. — El  Dorado  County. 

This  county,  which  lies  between  Amador  on  the  south  and  Placer  on 
the  north,  comprises  that  portion  of  the  Sierra  which  extends  between 
the  Cosunmes  River  and  the  middle  fork  of  the  American.  Its  western 
boundary  is  near  the  edge  of  the  foot-hills.  In  the  general  features  of 
its  geology  it  differs  very  little  from  the  counties  to  the  south,  which 
have  already  been  noticed.  The  volcanic  formations  are  less  exten¬ 
sively  developed  than  they  are  in  Amador,  although  there  are  still  the 
remains  of  at  least  one  heavy  flow  of  lava  to  be  traced  through  the  cen¬ 
tral  part  of  the  county. 

The  belt  of  auriferous  rocks  in  El  Dorado  is  quite  broad,  having  an 
average  width,  at  right  angles  to  its  direction,  of  perhaps  thirty  miles ; 
the  slates  predominate  in  it,  and  in  the  canons  of  the  American  and 
its  branches  they  are  eroded  to  an  immense  depth.  With  the  slates 
occur  many  masses  of  sandstone,  in  various  stages  of  metamorphism ; 
occasionally  limited  patches  of  both  these  rocks  are  found,  retaining 
almost  entirely  their  original  condition,  as  far  as  chemical  composition 
and  mechanical  aggregation  are  concerned.  They  are  always,  however, 
turned  up  on  edge,  and  dip  invariably  to  the  east,  usually  at  an  angle 
of  from  70°- to  80°.  The  strike  of  the  slates,  through  the  principal 
mining  districts,  seems  to  vary  from  N.  20°  W.  to  N.  80°  W.  In  the 
vicinity  of  Placerville  it  is  IV  21°  W.  Here  the  rock  is  of  a  dark  color, 
very  finely  laminated,  and  containing  occasional  crystals  of  pyrites. 

As  far  as  the  palaeontological  evidence  which  has  been  collected  by 
the  Survey  can  be  relied  on,  a  part  at  least  of  these  slates  is  of  Triassic 
age.  No  undoubted  Jurassic  fossils  have  been  obtained  in  them, 
although  Mr.  Gabb  discovered,  about  two  miles  west  of  Spanish  Flat, 
some  imperfect  remains  of  Cephalopods,  which  could  not  be  distin¬ 
guished  from  the  Belenmites  found  on  the  Mariposa  Estate,  in  rocks 
known  from  the  other  fossils  associated  with  them  to  be  of  J urassic  age. 

Mr.  Gorham  Blake  obtained  at  Spanish  Flat,  from  the  light-colored, 
fissile,  and  slightly  metamorphic  slates,  a  very  distinct  impression  of 
what  appears  to  be  the  same  Goniatite  ( Goniatites  Icevidorsatus)  found  at 
Washoe  and  in  the  Humboldt  Mining  Region  of  Nevada.  A  similar 


280 


GEOLOGY  OF  THE  SIERRA  NEYADA. 


specimen,  from  near  Coloma,  was  given  to  Dr.  Trask  by  Hon.  John 
Conness,  and  Dr.  Horn  collected  what  appears  to  be  the  same  thing 
from  the  mountains  east  of  Owen’s  Valley.  In  the  case  of  the  Califor¬ 
nia  specimens,  the  condition  of  the  fossils,  which  are  impressions  on 
the  surface  of  the  slate,  is  such  as  to  preclude  the  possibility  of  accu¬ 
rate  determination  of  the  species ;  but,  from  the  general  resemblance  of 
all  of  them  to  each  other,  it  is  highly  probable  that  they  are,  if  not  the 
same,  at  least  closely  allied  species.  It  is  hardly  possible  to  avoid  the 
inference  that  a  very  considerable  portion  of  the  auriferous  slates,  in 
the  heart  of  the  Gold  Region,  is  of  Triassic  age,  especially  as  a  large 
number  of  fossils,  unquestionably  of  this  period,  have  been  obtained 
by  the  Survey  in  the  auriferous  slate  series  farther  north,  in  Plumas 
County.  The  evidence  at  the  last-named  locality  is  conclusive  in  favor 
of  the  exact  equivalence  in  age  of  a  part,  at  least,  of  the  gold-bearing 
rocks  of  California  to  the  formations  of  the  Humboldt  Mountains, 
which  we  know,  from  a  great  abundance  of  fossils  collected,  to  belong 
to  the  Upper  Trias,  and  to  be  the  equivalent  of  the  Hallstadt  and  St. 
Cassian  beds  of  the  Alps.* 

The  work  of  tracing  out  all  the  subdivisions  of  the  auriferous  slate 
series  through  the  mining  counties  remains  yet  to  be  done,  having 
been  just  commenced  in  the  southern  district.  It  will  require  a  vast 
amount  of  time  and  labor  fully  to  work  out  all  these  details  and  to  trace 
the  different  members  of  the  group,  broken  and  obscured  as  they  are  by 
metamorphic  agencies.  It  is  reasonable  to  suppose  that  minute  and 
thorough  search  will,  in  the  course  of  years,  furnish  the  necessary  palae¬ 
ontological  material  by  which  these  subdivisions  can  be  distinguished 
from  each  other;  but  it  is  not  to  be  denied  that  fossils  are  extremely 
rare  in  the  auriferous  rocks,  and  it  should  be  remembered  that,  at  the 
commencement  of  this  Survey,  there  was  not  a  particle  of  evidence  in 
existence  as  to  the  age  of  the  great  metalliferous  formations  of  the 
Pacific  coast,  nor  a  single  locality  of  fossils  known  to  exist  in  rocks 
which  could  be  unequivocally  connected  with  them. 

The  region  in  the  southwestern  and  western  portions  of  Placer 
County  is  occupied  by  obscure,  highly  metamorphic  rocks,  wdiich  have 

*  See  Palaeontology  of  California,  vol.  i,  section  2,  for  a  description  of  these  Triassic 
fossils,  by  Mr.  Gabb. 


THE  WESTERN  SLOPE  —  EL  DORADO  COUNTY. 


281 


as  yet  been  very  little  examined.  A  broad  belt  of  granite  makes  its 
appearance  on  their  western  edge,  and  is  well  exposed  in  the  bed  of 
the  American  River  at  and  near  Folsom.  Intrusions  of  granite  arc 
also  frequent  among  the  metamorphic  rocks  themselves;  but  they  can¬ 
not  be  located  until  we  have  a  map  on  which  to  lay  them  down. 

The  limestone  formation  of  the  Sierra  occurs  in  detached  masses 
through  Placer  County,  appearing  to  form  two  distinct  belts  nearly 
parallel  with  each  other  and  about  ten  miles  apart.  One  of  these  belts 
is  seen  near  Ringgold,  where  it  forms  an  apparently  disconnected  mass, 
covering  about  a  square  mile  of  surface.  The  strata  are  evidently 
much  broken  here,  as  the  strike  of  the  beds  of  limestone  is  to  the  east 
of  north ;  their  dip  is  to  the  east,  at  an  angle  of  50°.  This  outcrop  is 
in  a  line  with  that  at  Indian  Diggings,  about  eighteen  miles  southeast, 
taking  the  average  strike  of  the  rocks  in  this  part  of  the  Sierra  as  a 
guide ;  but  it  is  not  known  that  the  limestone  actually  makes  its  ap¬ 
pearance  anywhere  between  these  two  localities.  Following  the  same 
direction  towards  the  north,  the  next  outcrop  known  is  at  Cave  Val¬ 
ley,  on  the  middle  fork  of  the  American ;  still  farther  on,  there  is  a 
large  mass  of  limestone  nearly  in  the  same  line,  at  Limekiln,  on 
Wolf  Creek,  near  Grass  Valley.  Between  this  last-mentioned  locality 
and  that  of  Pence’s  Ranch,  already  described,  we  have  not  yet  been 
able  to  ascertain  the  existence  of  any  evidence  of  the  continuity  of  the 
belt  in  question,  although  all  these  localities  are  pretty  nearly  in  the 
same  position,  with  regard  to  each  other,  that  they  would  have  if  they 
had  all  been  originally  parts  of  one  continuous  group  of  strata. 

The  other  belt  crops  out  in  Marble  Valley,  a  side- valley  of  Deer 
Creek,  near  Clarksville,  about  eight  miles  east-southeast  from  Folsom. 
This  crosses  the  south  fork  of  the  American  River  near  Salmon  Falls, 
and  has  been  traced  no  farther  in  that  direction.  After  an  accurate 
map  of  this  portion  of  the  State  shall  havb  been  made,  it  will  be  ex¬ 
tremely  interesting  to  lay  down  upon  it  these  detached  outcrops,  and 
to  trace  their  connection  with  each  other.  At  present  it  can  only  be 
done  in  the  most  imperfect  manner;  but  the  results,  like  those  already 
hinted  at  in  noticing  the  great  quartz  vein  or  bed  of  the  Sierra,  give  a 
clue  to  an  immense  edgewise  or  longitudinal  thrust,  which  the  mass  of 
the  Sierra  Nevada  must  have  undergone,  by  which  vast  bodies  of 


GEOL.  VOL.  I. — 36 


282 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


strata,  once  continuous  for  hundreds  of  miles,  have  been  torn  asunder, 
portions  of  them  engulfed,  and  the  remainder  twisted  so  as  to  lie  at 
all  angles  with  regard  to  the  original  line  of  direction  of  the  mass,  hut 
not  so  far  removed  from  their  former  position  as  to  leave  any  doubts  of 
their  having  been  once  parts  of  the  same  continuous  formation. 

El  Dorado  does  not,  at  present,  occupy  a  very  important  position  as 
a  mining  county,  although  it  was  here  that  the  first  discovery  was 
made  which  led  to  the  opening  of  the  gold-fields  of  the  Sierra.  Most 
of  the  river  and  gulch  mines  are  pretty  nearly  exhausted ;  hut  there  is 
still  considerable  hydraulic  mining  going  on  at  various  points. 

There  were  formerly  a  large  number  of  quartz  mills  in  operation  in 
the  county;  but,  in  1861,  at  the  time  of  Mr.  Ashburner’s  examination, 
there  were  few  of  them  still  running.  Of  late,  however,  attention  has 
been  again  turned  in  this  direction,  and  it  would  appear  that  there  are 
many  gold-bearing  quartz  veins,  some  of  which  may  be  worked  with 
profit,  under  systematic  and  judicious  management. 

The  following  is  a  synopsis  of  all  that  was  doing  in  the  county,  in 
1861,  in  the  way  of  quartz-mining.  At  Logtown,  seven  miles  south¬ 
west  of  Placerville,  there  are  several  veins  in  the  granite.  Four  of 
these,  known  as  the  Empire,  Pocahontas,  Excelsior,  and  El  Dorado, 
have  been  worked,  at  intervals,  since  1850.  Their  general  direction  is 
northwest  and  southeast,  and  their  dip  is  to  the  east.  The  rock  was 
said  to  yield  $10  per  ton,  and  it  was  worked  in  a  ten-stamp  mill,  run 
by  steam,  the  cost  of  crushing  and  amalgamating  being  $1.49  per  ton. 

A  mill  at  Aurum  City,  one  and  a  half  miles  east  of  Logtown,  called 
the  Union  Mill,  was  run  on  a  small  but  rich  vein,  which  was  said  to 
yield  $30  a  ton.  The  mill  had  ten  stamps,  and  the  cost  of  treatment  of 
the  quartz  was  $2.05  per  ton. 

Another  mill  visited  by  Mr.  Asliburner,  was  at  Grizzly  Flat,  sixteen 
miles  in  a  direct  line  east-southeast  of  Placerville,  on  Steely’s  Fork,  a 
branch  of  the  Cosumnes  River.  The  vein  is  in  the  granite,  and  con¬ 
tains  a  large  amount  of  the  sulphurets  of  iron,  lead,  and  zinc;  it  was 
said  to  have  paid  very  well  near  the  surface,  where  these  combinations 
were  in  a  decomposed  condition.  The  mill  had  eleven  stamps,  and  was 
run  by  water-power. 


The  volcanic  formations, 


with  the  underlying  auriferous  detritus,  do 


THE  WESTERN  SLOPE - PLACER  COUNTV. 


283 


not  occupy  a  very  extensive  area  in  El  Dorado.  Some  patches,  how¬ 
ever,  still  remain  and  are  worked  by  the  hydraulic  method.  A  good 
example  of  these  may  be  seen  in  the  hills  about  Placerville,  and  be¬ 
tween  that  place  and  Diamond  Springs.  At  Reservoir  Hill,  two  miles 
north  of  the  town,  there  is  a  stratum  of  auriferous  gravel  forty-five 
feet  thick,  which  contains  gold  through  nearly  its  whole  mass.  It  is 
surmounted  by  a  bed  of  volcanic  breccia,  ten  feet  thick,  and  this,  in 
turn,  is  covered  by  a  thin  stratum  of  rounded  fragments  of  lava,  the 
whole  appearance  indicating  the  thinning  out,  or  the  lower  edge,  of  one 
of  the  ^reat  volcanic  masses  coniine;  down  from  the  Sierra. 

In  the  ridge  south  of  Placerville,  at  a  height  of  375  feet  above  the 
town,  similar  volcanic  beds  maybe  seen,  but  much  thicker,  and  covering 
heavy  accumulations  of  auriferous  gravel,  which  have  been  and  still  are 
somewhat  extensively  worked.  The  principal  features  here  are  not  ma¬ 
terially  different  from  those  exhibited  in  the  deposits  of  a  similar  cha¬ 
racter  in  the  counties  to  the  south.  The  rim-rock  is  very  marked  on 
the  north  side  of  the  hill,  and  is  at  least  seventy  feet  high  above  the 
bottom  of  the  auriferous  gravel,  and  perhaps  considerably  more.  At 
one  point  enormous  rounded  boulders  of  quartz  were  observed  resting 
directly  on  the  bed-rock ;  one  of  these  measured  fifteen  feet  long  by 
five  feet  wide  and  high.  These  deposits  now  occupy  the  summits  of 
high  ridges,  the  adjacent  country  having  been  worn  down  to  a  perpen¬ 
dicular  depth  of  several  hundred  feet  below  the  beds  of  detritus,  which 
must  originally  have  been  deposited  in  a  valley,  but  which  now  form 
the  culminating  points  of  the  region. 


Section  VIII. — Placer  County. 

This  county  has  Bear  River  on  the  north,  and  the  middle  fork  of  the 
American  on  the  south ;  it  stretches  east  and  west  from  the  State  line 
to  the  Sacramento  River.  It  is  very  narrow  from  north  to  south  through 
its  central  portion,  so  that  the  auriferous  slate  formation  is  not  well 
exposed,  the  volcanic  deposits  occupying  a  large  area,  and,  through  the 
lower  part  of  the  county,  all  of  the  elevated  table  between  the  north 
and  middle  forks  of  the  American.  Hence,  hydraulic  mining  is  the 


1^84 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


leading  interest  of  the  county;  there  are  hut  few  quartz-mines,  and 
none  of  these  have  been  in  operation  when  visited  by  us. 

Below  the  junction  of  the  two  forks  of  the  American,  the  metamor- 
phic  rocks  are  well  exposed,  from  Auburn  to  the  northwest.  In  this 
vicinity  the  predominating  formation  is  a  dark-colored  ferruginous, 
silicious  slate,  sometimes  passing  into  hornblende-slate,  often  very  com¬ 
pact  and  difficult  to  break.  The  dip  is  nearly  vertical,  and.  the  strike 
varies,  in  different  localities  at  no  great  distance  from  each  other,  from 
V.  20°  W.  to  H.  45°  W.  The  slates  extend  to  about  three  miles  south¬ 
west  of  Auburn,  where  granite  comes  in  and  continues  to  the  eds;e  of 
the  plain  of  the  Sacramento.  The  surface  underlain  by  this  rock  forms 
low,  rounded  hills,  and  the  depressions  between  them  are  partly  filled 
with  granitic  sand  and  detritus.  The  granite  often  weathers  out  in 
large,  boulder-like  masses,  which  are,  in  places,  split  up  and  used  for 
building  purposes.  Quarries  have  been  opened,  along  the  line  of  the 
Pacific  Railroad,  for  supplying  stone  for  the  State  House  at  Sacra¬ 
mento,  and  the  material  seemed  to  be  both  durable  and  handsome,  as 
far  as  could  be  judged  from  an  examination  of  specimens  taken  near 
the  surface. 

Large  masses  of  serpentine  occur  among  the  metamorphic  rocks 
near  the  granite  to  the  north  of  Auburn.  Iron  ore  was  also  observed 
in  this  vicinity,  of  excellent  quality,  and  in  larger  quantity  than  has  as 
yet  been  discovered  anywhere  in  the  auriferous  slate  series.  The 
locality  is  on  the  land  of  Lysander  Utt,  about  one  mile  north  of 
Wells’s  Ranch,  which  is  on  the  Grass  Valley  road,  six  miles  from  Au¬ 
burn.  The  ore  crops  out  on  a  side-hill,  and  forms  a  mass  more  than 
thirty  feet  thick,  of  which  the  longitudinal  extent  is  not  known,  although 
it  is  evidently  considerable.  It  is  a  hematite,  perhaps  mixed  with  some 
limonite,  and  has  not  yet  been  analyzed ;  it  appears,  however,  to  be  of 
excellent  quality,  and  is  remarkably  pure  and  free  from  intermixture 
with  rock.  With  the  present  prices  of  fuel  and  labor,  it  is  not  easy  to 
say  how  soon  California  will  be  able  to  manufacture  her  own  iron;  but 
this  locality  is  perhaps  more  favorably  situated  than  any  yet  discovered 
in  the  State  for  trying  the  experiment. 

The  metamorphic  rocks  are  finely  exposed  in  the  tremendous  canons 
of  both  the  north  and  the  south  forks  of  the  American  River;  these 


THE  WESTERN  SLOPE - PLACER  COUNTY. 


285 


gorges  or  canons  (valleys  they  cannot  properly  be  called)  have  been 
worn  out  in  the  slates,  since  the  epoch  of  volcanic  activity  in  the  Sierra, 
to  the  depth  of  from  1800  to  2500  feet.  •  Their  sides  have  exceedingly 
steep  slopes,  sometimes  averaging  as  much  as  30°  for  the  entire  dis¬ 
tance,  and  are  swept  entirely  clean,  there  being  usually  hardly  a  trace  of 
detritus  left  along  their  sides.  The  bottoms  of  these  canons  are  rarely 
more  than  wide  enough  to  allow  of  the  passage  of  the  rivers  which 
flow  through  them,  and  which  at  times  of  high  water  have  their  volume 
immensely  increased.  It  is  when  a  stream  like  the  American  rises 
twenty,  thirty,  or  even  as  much  as  fifty  feet  above  its  ordinary  stage, 
and  tears  down  its  highly  inclined  bed  with  incredible  force  and  ve¬ 
locity,  that  one  can  understand  how  these  canons  have  been  excavated ; 
and  if,  as  we  have  reason  to  believe,  a  much  larger  amount  of  rain  fell 
on  the  Sierra  in  former  times  than  now  does,  it  is  easy  to  see  what  the 
eroding  power  of  these  streams  must  have  been,  in  those  days  when 
the  great  glaciers,  which  once  covered  so  large  a  portion  of  the  moun¬ 
tains  above,  were  melting  away. 

Along  the  middle  fork  of  the  American,  as  far  as  a  Forest  Hill  under 
the  Hill,”  the  volcanic  and  detrital  beds  come  down  to  the  edge  of  the 
summit  of  the  canon.  A  little  farther  on,  near  Saralisville,  they  recede 
to  the  north,  and  there  are  ample  exposures  of  the  auriferous  slates. 
An  immense  ridge  of  serpentine  occurs  near  the  last-mentioned  place, 
forming  the  largest  mass  of  this  rock  seen  in  the  State. 

Quite  a  number  of  quartz  veins  have  been  worked  here  at  various 
times;  but  they  were  all  abandoned  when  examined  by  us  in  1861.  It 
is  probable  that  some  of  these  have  been,  or  will  be,  taken  up  again, 
and  new  discoveries  in  this  region  have  been  reported,  indicating  that  the 
quartz-mining  business  may  be  revived  with  success  in  Placer  County. 

An  important  chain  of  hydraulic  diggings  passes  through  Placer 
County,  from  north  to  south,  on  which  the  workings  have  been,  and 
still  are,  quite  extensive.  The  principal  mining  towns  are  Iowa  Hill, 
Wisconsin  Hill,  Yankee  Jim’s,  and  Todd’s  Valley.  The  thickness  of 
the  detrital  and  volcanic  formations  on  this  line  must  be,  in  places, 
over  500  feet.  Some  of  the  washings  exhibit  a  vertical  section  of  over 
a  hundred  feet  in  thickness  of  “  cement,”  or  coarse  gravel  and  boul¬ 
ders,  often  quite  firmly  compacted  together.  Over  this  are  the  usual 


28G 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


beds  of  sedimentary-volcanic  materials,  and  above  all  the  capping  of 
bard  basaltic  lava,  which  forms  the  table  of  the  divide  between  the 
north  and  middle  forks  of  the  American,  and  of  which  the  thickness  has 
not  been  measured,  for  want  of  a  good  exposure. 

The  lava  tables  seem  to  extend  far  to  the  east,  and  are  seen  finely 
exposed  in  the  vicinity  of  Deadwood,  Last  Chance,  and  other  mining 
camps  high  up  on  the  divide.  Here  the  canons  are  very  numerous, 
and  have  exceedingly  steep  sides.  Near  Deadwood  the  depth  of  one 
was  measured  and  found  to  be  a  little  over  1600  feet.  El  Dorado 
Canon,  a  little  farther  down,  was  nearly  2000  feet  deep;  the  steepness 
of  the  sides  of  these  gorges  maybe  inferred  from  the  fact  that  the  upper 
eds:es  of  the  walls  of  the  last-mentioned  one  were  not  over  three-fourths 
of  a  mile  apart,  which  would  make  the  average  slope  of  the  walls  but 
little  less  than  45°.  In  these  canons  a  very  interesting  fact  was  ob¬ 
served,  which  may  be  found  to  have  an  important  bearing  on  the  strati¬ 
graphy  of  the  Sierra.  It  was  noticed,  namely,  that  where  the  aurifer¬ 
ous  slates  were  seen  in  an  almost  vertical  section  of  over  1500  feet,  the 
upper  1000  or  1200  only  had  the  usual  normal  dip  of  the  formation, 
or  to  the  east,  at  a  high  angle ;  below  this  there  was  a  gradual  curve, 
and  at  the  bottom  the  inclination  was  decidedly  to  the  west,  just  as 
would  be  expected  to  be  the  case  if  the  upper  portion  of  the  slates  had 
been  forced  back  by  immense  pressure  from  above,  producing  a  condi¬ 
tion  of  things  similar  to  that  so  often  observed  in  the  Alps,  which  is 
known  as  the  “  fan-structure,”  and  has  so  much  perplexed  geolo¬ 
gists.  Many  facts  of  a  similar  kind  to  this  have  been  noticed  in  the 
Sierra,  although  nowhere  on  so  large  a  scale  as  in  Placer  County, 
which  may  perhaps  be  accounted  for  by  the  tact  that  there  are  hardly 
anywhere  such  good  opportunities  for  observations  of  the  dip  at  so 
great  a  depth  from  the  surface. 

Of  the  intricacy  of  the  topography  to  which  these  numerous  deep 
canons  give  rise,  one  can  hardly  form  any  idea,  who  has  not  undertaken 
the  task  of  laying  them  down  upon  a  map.  None  of  the  mining  camps 
in  this  part  of  the  county  have  been  located  with  any  approach  to  accu¬ 
racy,  and  the  names  of  most  of  them  will  be  sought  for  in  vain  upon 
any  published  map.  After  some  approach  to  a  correct  delineation  of 
the  surface  has  been  made  by  the  Survey,  it  will  be  an  exceedingly 


THE  WESTERN  SLOPE - NEVADA  COUNTY. 


287 


interesting  work  to  connect,  together  the  various  ancient  river  channels 
and  lake-like  expansions,  which  are  now  tilled  up  with  these  vast  accu¬ 
mulations  of  detritus,  and  thus  to  reconstruct  the  system  of  water¬ 
courses  by  which  the  Sierra  was  furrowed,  at  a  time  when  the  condi¬ 
tions  were  so  different  from  what  they  now  are.  It  may  be  allowable 
to  direct  attention  to  the  practical  value  of  such  a  work,  as  a  means  of 
guiding  the  miner  in  his  explorations,  and  as  giving  a  clue  to  the 
probable  extent  and  duration  of  the  hydraulic  washings;  but  it  seems 
almost  useless,  with  our  present  paucity  of  data,  to  enter  into  any  specu¬ 
lations  on  this  subject. 

At  Todd’s  Valley,  and  at  Yankee  Jim’s,  the  character  of  the  detrital 
deposits  and  of  the  underlying  slates  may  be  very  well  studied,  as  exten¬ 
sive  areas  of  the  latter  have  been  exposed  by  the  washings.  At  Yankee 
Jim’s,  not  less  than  300  acres  have  had  stripped  from  them  a  covering 
of  “  cemented  gravel,”  which  was  rarely  less  than  twenty-five,  and  in 
places  as  much  as  a  hundred  feet  thick.  The  pebbles  and  boulders  of 
this  gravel  are  all  thoroughly  water-worn,  and  consist  to  a  large  extent 
of  quartz ;  this  was  observed  to  be  especially  the  case  at  Michigan 
Bluffs.  The  bed-rock,  which  is  here  a  light-colored  talcose,  or  silicious 
slate,  decomposes  very  easily,  and,  in  some  places,  can  be  excavated 
with  a  pick  down  to  a  depth  of  twenty  feet  from  the  surface.  The 
occurrence  of  impressions  of  leaves  and  masses  of  wood,  more  or  less 
completely  silicified,  in  the  detrital  deposits,  is  frequently  noticed,  where 
the  material  is  not  too  coarse. 


Section  IX. — Xevada  County. 


We  pass  to  the  next  county  north  of  Placer,  that  of  Xevada,  of  which 
both  the  quartz-mines  and  the  hydraulic  washings  are  among  the  most 
important  in  the  State;  and  where,  as  the  people  were  never  so  largely 
dependent  on  ordinary  placer  diggings  for  employment  as  they  were  in 
most  other  portions  of  the  mining  region,  there  has  not  been  that  falling 
off*  in  general  prosperity  of  which  some  other  counties  have  had  to 
complain. 

Xevada  County  includes  the  region  between  Bear  River  and  the 


288 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


Middle  Yuba;  its  western  boundary  is  a  north  and  south  line,  parallel 
with  the  course  of  Feather  River,  and  about  twenty  miles  east  of  it. 
It  extends  east  to  the  State  line.  The  absence  of  any  tolerable  map  of 
the  county  renders  it  difficult  to  do  more  than  to  give  some  detached 
observations  on  the  geology  of  this  interesting  region ;  but  we  propose 
to  commence  here,  with  one  of  our  parties,  our  detailed  work  of  the 
next  season,  connecting  on  the  south  with  the  topographical  surveys  of 
Mr.  Wackenreuder,  who  has  been  engaged,  during  portions  of  two 
years,  in  mapping  for  the  Survey  the  region  between  the  Silver  Moun¬ 
tain  Road  and  Truckee  Pass. 

The  auriferous  belt  in  this  county  is  very  wide ;  but  it  has  large  areas 
of  granite  included  within  it,  much  larger  than  any  in  the  counties  to 
the  south.  The  principal  one  of  these  granitic  belts  passes  a  little  east 
of  Grass  Valley  and  extends  by  San  Juan  North,  to  Feather  River. 
Between  these  belts,  the  slates  are  highly  metamorphosed,  and  the 
sandstones  sometimes  pass  into  granitoid  rocks,  forming  masses  which 
can  hardly  be  distinguished  from  true  granite ;  as  in  the  Sebastopol 
Claim,  about  a  mile  and  a  half  west  of  San  Juan,  where  the  bed-rock 
is  finely  exposed  by  the  removal  of  the  overlying  detritus,  and  shows 
a  considerable  number  of  parallel  bands  of  slate  and  metamorphic 
gneissoid  rock.  The  formation  has  a  vertical  dip  at  this  point,  and  the 
strike  of  the  beds  is  nearly  north  and  south.  Where  the  slates  are 
highly  altered,  as  in  the  vicinity  of  Grass  Valley,  it  is  very  difficult  to 
say  what  is  their  true  position. 

Farther  to  the  east,  where  the  metamorphism  has  not  been  so  com¬ 
plete,  the  slates  occupy  a  very  extensive  area,  the  limits  of  which  have 
not  yet  been  defined. 

The  limestone  belt  may  be  traced  through  the  southwestern  part  of 
the  county ;  and  there  are  indications  of  another  one  much  higher  up 
in  the  mountains  ;  but  which  cannot  as  yet  be  accurately  located.  The 
band  of  limestone,  which  is  well  exposed  at  the  place  known  as  “Lime¬ 
kiln,"  about  ten  miles  south  of  Grass  Valley,  appears  to  be  in  the  same 
line  with  that  of  Pence’s  Ranch,  which  is  known  by  its  fossils  to  be  of 
Carboniferous  ao;e. 

It  is  evident  that,  as  we  go  north  from  Placer  County,  we  fipd  the 
slates  and  other  rocks  of  the  metamorphic  series  extending  farther  and 


THE  WESTERN  SLOPE - NEVADA  COUNTY. 


289 


farther  to  the  east,  encroaching  upon  the  granitic,  so  to  speak,  or  occu¬ 
pying  the  place  which  that  rock  would  have,  if  the  trend  of  the  great 
granitic  mass  of  the  Sierra  remained  the  same  which  it  is  farther  to 


the  south.  Thus,  when  we  reach  Sierra  and  Plumas  Counties,  we 
shall  see  that  there  are  heavy  belts  of  both  slates  and  sandstones,  fossil- 
iferous  in  places,  which  occupy  the  crest  of  the  Sierra,  that  is  to  say, 
the  line  along  which  are  situated  the  highest  peaks  of  the  chain,  although 
this  is  not  here  the  real  water-shed,  which  lies  to  the  east  of  this,  the 
Feather  River  breaking  through  the  main  ridge  and  heading  far  to 
the  east,  between  a  series  of  ridges  which  form  great  spurs  of  the 
Sierra  and  stretch  off  to  the  north  into  a  region  which,  as  yet,  has  been 
but  little  explored.  The  strike  of  the  rocks  also  becomes  more  nearly 
north  and  south  as  we  follow  the  Sierra  northwards,  everything  indicat¬ 
ing  the  gradual  giving  out  of  the  system  of  northwest  and  southeast 
trends,  which  has  impressed  itself  so  strongly  on  the  geography  and 
geology  of  the  State  in  the  southern  portion  of  the  Sierra,  and  a  prep¬ 
aration  for  the  north  and  south  axes  of  upheaval,  by  which  the  moun¬ 
tain  ranges  of  Western  Nevada,  as  well  as  of  Northeastern  California 
and  Oregon,  have  been  fashioned. 

The  same  easterly  dip  which  characterizes  the  rocks  of  the  Central 
Sierra,  seems,  however,  to  prevail  all  through  this  northern  region,  at 
least  on  the  western  side  of  the  crest,  and  it  would  appear  that  the  in¬ 
clination  is  generally  higher  along  the  lower  edge  of  the  belt,  being 
nearly  vertical  in  many  places  in  the  vicinity  of  San  Juan.  This  high 
dip  of  the  slates  seems  to  be  connected  with  the  appearance  of  the 
granitic  belts  along  the  western  edge  of  the  Sierra,  which  rock  becomes 
more  and  more  predominant,  as  we  proceed  towards  the  northwest, 
and,  crossing  the  Sacramento,  enter  the  lofty  and  broken  region  of 
Trinity  and  Del  Norte  Counties. 

Grass  Valley  has  been,  and  is  still,  the  headquarters  of  the  quartz¬ 
mining  business ;  there  are  many  mills  here,  and  most  of  them  have 
been  successful.  In  1861  the  mills  of  this  vicinity  furnished  about 
$1,500,000  of  gold,  which  was  about  one-fourth  of  the  entire  produc¬ 
tion  of  the  California  quartz-mines.  Reserving  all  details  in  regard  to 
this  business  for  a  future  volume,  some  of  the  more  important  facts  in 
regard  to  the  mines  and  mills  of  Grass  Valley,  as  they  were  in  1861, 


GEOL.  VOL.  I. — 37 


290  GEOLOGY  OF  THE  SIERRA  NEVADA. 

may  be  communicated  from  Mr.  Ashburner’s  notes.  The  processes 
employed  in  these  mills  are  different  from  those  generally  adopted  in 
other  parts  of  the  State,  amalgamating  in  the  batteries  not  being  in 
favor  here.  The  richness  of  the  veins  in  this  vicinity,  and  their  small 
size,  rendering  extraction  expensive,  have,  more  than  elsewhere  in  the 
Gold  Region,  made  it  necessary  for  the  proprietors  of  the  mines  and 
mills  to  use  every  possible  means  to  improve  their  machinery,  so  as  to 
save  the  largest  possible  amount  of  the  precious  metal  at  the  least 
expense.  Almost  every  new-fangled  idea,  in  the  way  of  crushers  and 
amalgamators,  has  been,  at  one  time  or  another,  thoroughly  tried  here, 
and  in  most  cases  with  more  loss  than  gain.  There  seems  to  be  a 
mania  among  inventors  in  this  country  for  trying  their  skill  on  matters 
of  which,  they  know  little  or  nothing,  and  in  no  department  of  the  me¬ 
chanical  art  has  this  been  more  conspicuous  than  in  that  which  relates 
to  the  treatment  of  auriferous  quartz.  It  would  require  volumes  to 
describe  all  the  ingenious  but  perfectly  useless  contrivances,  each  of 
which  has,  in  its  day,  been  considered  as  about  to  revolutionize  the 
quartz  business;  these  have  nearly  all  either  entirely  disappeared, 
where  there  was  luckily  a  foundry  near  enough  to  make  the  metal  of 
which  they  were  constructed  available  as  old  iron,  or  else  lie  as  heaps 
of  rubbish  about  the  premises  of  the  too  confiding  miners. 

There  will  be  hardly  any  way  in  which  the  Survey  can  be  of  more 
immediate  pecuniary  benefit  to  the  State,  than  in  making  a  thorough 
investigation  of  the  principles  which  underlie  the  business  of  crushing 
and  amalgamating  gold  ores,  and  thus  settling  some  of  the  questions 
which  are  always  coming  up  among  the  owners  of  mills  and  mines,  as 
to  what  forms  of  machinery  will  be  best  adapted  to  working  the  class 
of  ores  with  which  they  have  to  deal ;  if  important  improvements  can¬ 
not  be  suggested,  at  least,  a  great  saving  may  be  effected  by  furnishing 
a  basis  of  facts  as  a  guide  to  inventors  into  the  right  direction  for  the 
employment  of  their  talents.  These  matters  do  not  properly  come  up 
for  cjiscussion  in  the  geological  volumes,  nor  have  our  means  been  suf¬ 
ficient  to  enable  us  to  do  mpre  than  make  a  beginning  in  this  line  of 
research.  A  few  facts  may,  however,  be  stated  in  this  connection  in 
regard  to  the  development  of  the  Grass  Valley  mines  and  mills. 

It  may  be  premised,  however,  that  the  quartz  lodes  in  this  vicinity 


THE  WESTERN  SLOPE  —  NEVADA  COUNTY. 


291 


are  not  large;  but  that  they  more  than  make  up  for  their  slight  devel¬ 
opment  in  width  by  their  increased  richness.  They  are  irregular  in 
their  yield,  as  is  evident,  not  only  from  the  examination  of  the  mines 
themselves,  hut  from  a  consideration  of  their  past  history.  The  pro¬ 
verbial  uncertainties  of  mining  would  he  well  illustrated  by  an  exact 
history  of  all  that  has  transpired  in  this  region  since  the  first  quartz 
mill  was  erected.  Fortunes  have  been  lost  by  working  mines  which 
seemed  to  exhibit  every  indication  of  yielding  large  returns ;  and  for¬ 
tunes  have  been  made  by  the  purchase,  at  nominal  sums,  of  lodes 
which  had  been  abandoned  as  worked  out  or  worthless.  An  idea  of 
some  of  the  peculiar  characters  of  these  veins  may  be  gathered  from 
what  here  follows:  but  of  their  relative  position  and  mutual  connection 
it  will  not  be  possible  to  give  any  intelligible  account,  until  a  map  of 
this  district,  on  a  large  scale,  shall  have  been  prepared,  and  the  results 
of  a  careful  survey  of  the  lodes  laid  down  upon  it. 

The  Allison  Ranch  Mine  is  perhaps  as  well  known  as  any  in  Califor¬ 
nia,  and  has  the  reputation  of  being  fabulously  rich.  As  no  authorized 
statements  of  its  yield  have  ever  been  published,  and  as  it  is  known  to 
have  produced  large  sums,  it  is  very,  natural  that  the  most  exaggerated 
ideas  should  have  been  formed  as  to  its  importance.  The  direction  of 
the  lode  is  from  5°  to  15°  to  the  west  of  north,  and  it  dips  to  the  west 
at  an  angle  of  40°  to  45°.  Its  average  thickness  is  said  to  be  about 
eighteen  inches;  when  examined  by  us,  in  1861,  it  was  about  twelve 
inches  wide  in  the  workings  at  the  bottom  of  the  shaft,  which  was 
then  214  feet  deep  on  the  incline.  In  1863,  this  shaft  had  been  sunk 
to  the  depth  of  360  feet.  The  ground  had  been  opened  on,  in  1861,  to 
a  distance  of  500  feet  north,  and  400  feet  south,  of  the  shaft.  The 
veinstone  is  almost  exclusively  quartz,  with  but  a  very  small  amount 
of  the  sulphuret  of  irom  The  lode  is  regular  and  well-defined,  having 
a  distinct  selvage  of  flucan  on  the  hanging-wall,  while  the  foot-wall  is 
less  distinctly  separated  from  the  “  country,”  or  inclosing  rock.  The 
yield  of  the  quartz  has  been  very  variable,  but  is  not  known  with  accu¬ 
racy  ;  it  is  believed  by  Mr.  Ashburner  to  have  averaged  about  $50  a  ton 
on  14,858  tons  stamped  between  March,  1857,  and  December,  1861 ;  the 
lowest  yield  was  estimated  at  $32  and  the  highest  at  $144  a  ton.  The 
rock  near  the  surface,  however,  is  known,  from  the  returns  of  the  cus- 


) 


292 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


tom  mill  where  it  was  worked,  to  have  paid  as  much  as  $375  per  ton. 
The  total  amount  of  bullion  deposited  by  the  proprietors  at  the  United 
States  Mint,  from  March  25,  1857,  to  December  2,  1861,  was  47,898.80 
ounces,  which  is  equal  to  $838,229;  estimating  its  value  at  $17.50  per 
ounce.  The  mill  has  eight  stamps,  driven  by  steam,  and  the  arrange¬ 
ments  for  saving  the  gold  are  similar  to  those  of  other  mills  in  the 
vicinity.  The  sulpliurets  are  saved  and  ground  in  large  pans.  A  rich 
spot,  or  “  bonanza,”  was  struck  in  1863,  and  the  quartz  was  then  said 
to  be  paying  $150  a  ton ;  previous  to  that,  for  some  time,  the  mine  had 
hardly  paid  expenses. 

Massachusetts  Hill  is  one  of  the  most  interesting  localities  in  Califor¬ 
nia,  and  the  mine  of  that  name  has  had  more  than  its  share  of  ups  and 
downs ;  but,  of  later  years,  has  been  exceedingly  productive.  The  vein 
has  a  very  flat  dip,  and  seems  to  form  a  kind  of  basin,  being  quite  dif¬ 
ferent  in  this  respect  from  any  of  the  lodes  seen  in  other  districts  of 
the  State.  Its  maximum  thickness  appeared  to  be  about  two  feet  and 
a  half,  and  where  best  developed,  it  was  divided  into  three  distinct 
floors  or  bands,  with  several  inches  of  rock  between  each.  It  would  be 
interesting  to  make  a  most  thorough  study  of  this  lode,  as  it  presents 
peculiarities,  the  exact  knowledge  of  which  could  hardly  fail  to  throw 
some  light  on  the  origin  of  quartz  veins  in  general.  The  mill  has  six¬ 
teen  stamps,  working  oil  the  average  850  tons  of  quartz  per  month  (in 
1861).  The  proportion  of  pyrites  in  the  Massachusetts  Hill  vein  is 
large,  averaging,  it  is  said,  as  much  as  five  or  six  per  cent.  The  aver¬ 
age  yield  of  the  quartz  was  stated  at  $70  a  ton,  and  the  amount  paid 
for  the  treatment  at  the  mill  was  $5,  the  mine  and  the  mill  not  belong¬ 
ing  (in  1861)  to  the  same  parties. 

The  Pacific  Quartz  Mining  Company  was  at  work,  in  1863,  on  a  vein 
east  of  Wolf  Creek,  and  within  the  town  of  Grass  Valley;  it  has  a 
northeast  and  southwest  strike,  and  dips  to  the  east  at  an  angle  of  39°. 
This  vein  varies  much  in  thickness,  but  averages  about  eighteen  inches. 
The  mine  had  been  opened,  in  1863,  to  the  depth  of  215  feet,  and  levels 
driven  each  way  fifty  and  eighty  feet.  The  rock  was  estimated  to  pay 
$40  a  ton. 

The  Hortli  Star  Mining  Company  is  located  about  two  miles  south¬ 
west  of  Grass  Valley.  The  vein  is,  like  all  others  in  this  region,  of 


TIIE  WESTERN  SLOPE - NEVADA  COUNTY. 


293 


variable  width,  sometimes  thinning  down  to  a  mere  seam,  and  again 
widening  to  six  feet.  The  quartz  was  said  to  pay  from  $15  to  $20  per 
ton,  and,  in  1863,  the  mine  had  been  opened  to  a  depth  of  400  feet 
on  the  incline,  and  a  length  of  325  feet.  The  mill  has  nine  stamps  and 
is  driven  by  steam. 

There  are  several  other  mines  in  this  vicinity  which  it  is  not  worth 
while  to  describe  in  this  place,  and  a  number  of  mills  which  run  on 
custom-work,  among  which  the  old  Gold  Hill  Mill  is  one  of  the  most 
venerable,  having  been  built  in  1853. 

There  are  also  important  mines  and  mills  near  Nevada  City,  and 
between  there  and  Grass  Valley,  of  which  one  or  two  will  be  noticed. 

The  mill  of  the  Nevada  Quartz  Mining  Company  is  on  the  right 
bank  of  Deer  Creek,  about  one  mile  below  the  city  of  Nevada.  The 
vein  from  which  it  is  supplied  is  in  the  granite,  and  is  situated  on  a 
steep  hill-side  directly  above  the  mill ;  it  runs  northwest  and  southeast, 
and  dips  to  the  northeast  at  an  angle  of  45°.  Its  average  width  is 
about  twelve  feet,  and  it  contains  a  considerable  amount  of  pyrites  and 
some  galena.  The  mill  has  twelve  stamps,  driven  by  water-power. 
The  average  yield  of  the  quartz  for  the  two  years  1862-3,  was  about  $15 
per  ton,  the  net  profits  for  the  year  ending  March,  1863,  being  a  little 
over  $67,000. 

Sneatli,  Clay  &  Co.’s  mill,  three-fourths  of  a  mile  southeast  of  Ne¬ 
vada  City,  was  built  in  1863,  and  was  considered  by  many  to  be,  at 
that  time,  the  best  arranged  and  most  thoroughly  built  quartz-mill  in 
California.  It  has  twelve  stamps,  and  is  run  by  steam-power.  The 
vein  is  near  the  mill,  and  has  a  dip  of  30°,  and  a  width  of  from  eighteen 
inches  to  two  feet.  It  yielded  very  finely,  near  the  surface  ;  but  we 
have  no  data  as  to  its  present  condition  and  prospects. 

As  the  proprietors  of  this  mill  were  generally  considered  to  have 
adopted  the  most  approved  processes  for  saving  the  gold,  it  may  be  worth 
while  to  give  a  concise  description  of  its  machinery,  as  communicated 
to  us  by  Mr.  H.  H.  Sheldon. 

The  stamps  are  constructed  on  the  revolving  principle,  and  are  ar¬ 
ranged  in  three  batteries,  of  four  heads  to  each.  Each  stamp-head  with 
its  iron  lifter  weighs  900  pounds,  and  strikes  sixty  blows  per  minute, 
the  mill  being  able  to  crush  twenty-four  tons  of  quartz  in  twenty-four 


294 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


hours.  In  front  of  each  battery  are  placed  two  runs  of  blanket  sluices, 
and  at  the  end  of  the  blankets  is  a  labyrinth,  of  which  the  bottom  is 
covered  with  copper  plates.  The  washings  of  the  blankets  are  caught 
in  large  wooden  vats,  and  from  thence  passed  through  an  “  Attwood’s 
amalgamator,”  and,  after  leaving  that,  through  four  Chilian  mills. 
The  muddy  water  that  flows  from  the  labyrinth  is  received  into  the 
same  trough  with  that  from  the  Chilian  mills,  and  the  whole  is  con¬ 
ducted  to  vats  where  the  slimes  have  an  opportunity  to  subside,  and 
the  water  flows  oft'.  The  material  deposited  in  the  vats  is  carried  by  a 
revolving  screw  to  five  Norton’s  pans,  and  what  escapes  from  these 
goes  on  to  four  Bradford’s  vanning  tables,  by  which  the  sulphurets  are 
completely  separated  from  the  earthy  particles,  which  are  then  allowed 
to  run  to  waste.  The  sulphurets  in  the  Grass  Valley  mines  are  usually 
sold,  and  treated  by  Plattner’s  chlorine  process.  If  not  rich  enough 
to  pay  for  working  by  that  method,  they  are  allowed  to  lie  and  become 
oxidized,  when  they  are  passed  through  the  pans  again. 

There  have  been  many  discoveries  of  copper  ores  in  Nevada  County 
within  the  last  two  or  three  years,  and  mining  has  been  commenced  at 
several  points,  where  there  seemed  to  be  very  promising  indications, 
and  only  capital  and  skill  lacking  to  develop  something  of  importance. 

The  district  to  which  the  most  attention  has  been  attracted  is  that 
near  the  “  Zinc  House,”  in  the  southwestern  part  of  the  county,  where 
quite  a  number  of  mines  were  worked  in  1863.  The  first  discovery 
seems  to  have  been  in  1857,  at  what  is  now  called  the  “  Well  Lode,” 
by  Mr.  D.  S.  Tallman.  Here  is  an  immense  body  of  pyrites,  of  a  len¬ 
ticular  shape,  having  its  longer  axis  in  the  direction  of  the  metamor- 
phic  slates  in  which  it  is  inclosed.  When  examined,  in  1863,  the  width 
of  the  mass  had  not  been  ascertained,  but  a  drift  had  been  extended 
for  a  distance  of  forty-eight  feet  across  the  deposit,  all  the  way  in  the 
solid  sulphurets,  and  the  western  limit  had  not  been  reached.  To  the 
east,  there  was  a  well-marked  wall,  with  a  selvage  of  flucan  between  it 
and  the  country,  five  inches  thick.  The  cupriferous  portion  of  this 
mass  seemed  to  be  on  its  borders ;  the  interior  was  almost  barren  of 
copper.  There  had  been  shipped,  up  to  that  time,  250  tons  of  ore, 
returns  from  sixty  of  which  had  been  received,  and  the  yield  of  copper 
was  stated  at  nine  and  a  half  per  cent. 


THE  WESTERN  SLOPE - NEVADA  COUNTY. 


295 


The  Eureka  Consolidated  Mining  Company  had,  in  1863,  a  claim 
5000  feet  in  length,  in  the  Empire  District,  about  two  and  a  half  miles 
north  of  the  Zinc  House.  The  vein  had  a  course  of  N.  17°  W.,  and 
dipped  to  the  east  at  a  very  high  angle.  At  the  depth  of  forty-six  feet, 
the  lode  was  four  feet  thick  and  well  filled  with  hunches  and  strings  of 
copper  pyrites,  giving  the  impression  of  a  large  and  valuable  deposit. 

The  Last  Chance  was  another  company,  with  a  proVnising  vein,  sup¬ 
posed  to  he  the  continuation  of  the  Eureka.  It  had  been  sunk  on  to 
the  depth  of  sixty-one  feet  in  October,  1863,  and  a  considerable  amount 
of  good  ore  had  been  taken  out.  There  were  many  other  claims  in 
this  vicinity,  where  mining  was  going  on  two  years  ago,  and  which 
would  have  been  considered,  in  the  Atlantic  States,  as  offering  excel¬ 
lent  inducements  for  the  investment  of  capital.  It  remains  to  be  seen 
how  far  the  high  rate  of  wages  in  California  and  the  scarcity  of  fuel 
and  water  about  these  mines  will  operate  to  check  their  development. 

Nevada  County  is  not  only  celebrated  for  its  rich  quartz-mines,  but 
it  has  some  of  the  most  extensive  hydraulic  washings  of  the  State  within 
its  borders,  being  second  only  to  Sierra  County  in  this  respect.  Un¬ 
luckily,  there  is  no  one  of  the  mining  counties  of  the  State  of  which 
the  published  maps  are  so  defective,  so  that  any  attempt  to  lay  down 
the  area  occupied  by  the  auriferous  detritus  in  this  region  would  be  at 
present  entirely  futile,  and  it  is  quite  impossible  to  estimate  the  amount 
of  ground  worked  out,  or  that  which  still  remains  to  be  washed,  when 
the  positions  of  the  places  where  the  washings  are  carried  on  cannot  be 
fixed  within  miles.  Should  the  Survey  be  continued,  this  will  be  the 
region  of  our  topographical  labors  during  the  next  season,  and,  in  time, 
we  may  hope  to  be  able  to  give,  what  all  would  admit  to  be  of  the 
greatest  interest,  a  connected  view  of  the  hydraulic  washings,  in  regard 
to  which  the  wildest  and  most  absurd  views  have  been  put  forth  by 
those  who  have  only  had  an  opportunity  of  making  a  superficial  exam¬ 
ination  of  them. 

Whether  the  u  Blue  Lead,”  or  the  great  ancient  river-bed  of  Sierra 
County,  so  well  known  throughout  California,  passes  through  Nevada 
also,  it  is  not  in  our  power  to  state.  It  undoubtedly  enters  this  county 
at  Snow  Point,  and  whether  it  continues  its  southerly  course  across  it, 
connecting  with  the  extensive  detrital  deposits  near  Bed  Dog,  and  then 


29G 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


is  continued  across  Placer  County,  finally  running  out  at  Todd’s  Val¬ 
ley,  remains  to  be  demonstrated.  Judging  from  our  present  knowl¬ 
edge,  such  a  course  of  this  great  river  of  the  Pliocene  Tertiary  epoch 
seems  not  improbable.  If  this  hypothesis  be  correct,  then  the  lake-like 
expansions  of  the  former  river,  like  that  near  Ped  Dog,  may  have  been 
caused  by  the  coming  down  of  side  streams  from  the  east,  in  the  direc¬ 
tion  of  the  summit  of  the  Sierra.  But  it  is  in  vain  to  attempt  to  recon¬ 
struct  the  ancient  topography  of  a  country,  of  the  present  surface  of 
which  we  have  only  the  roughest  outlines. 

The  hydraulic  washings  at  Chalk  Bluffs,  near  Red  Dog,  are  espe¬ 
cially  interesting  on  account  of  the  immense  number  of  large  trunks 
of  trees  which  have  been  buried  there,  and  which  have  been  -uncovered 
by  the  miner’s  work.  There  are  also  beds  of  fine  sediments  here, 
inclosing  many  impressions  of  leaves,  of  which  a  large  collection  has 
been  made  for  future  examination.  The  remains  of  animals  seem  to  be 
much  less  abundant  in  the  northern  counties  than  they  are  farther  south  ; 
but  this  is  the  only  locality  where  we  have  seen  the  evidences  of  the 
overwhelming  of  a  whole  forest  by  the  rush  of  the  waters  from  the 
Sierra.  The  stems  and  branches  are  all  silicified,  and  bear  the  marks 
of  having  been  exposed  to  violent  currents  before  they  were  imbedded 
in  the  detritus  which  now  covers  them. 

The  auriferous  gravel  underlying  the  volcanic  formations  has  been 
extensively  washed  in  the  vicinity  of  Nevada  City,  and  also,  but  on  a 
smaller  scale,  near  Grass  Valley.  The  mines,  at  the  first-mentioned 
place,  are  around  the  base  of  the  Sugar  Loaf,  a  conical  knob  at  the  end 
of  a  ridge  of  lava,  which  covers  a  mass  of  sedimentary-volcanic  mate¬ 
rials  with  deposits  of  gravel  at  the  bottom.  The  Sugar  Loaf  itself  is 
603  feet  above  the  level  of  Deer  Creek,  at  Nevada  City,  and  the  upper 
hundred  feet  is  a  solid  mass  of  lava.  The  bed-rock  of  the  region  is 
granite,  which  weathers  in  huge,  rounded  masses,  like  boulders,  and 
shows  this  kind  of  surface  wherever  the  superincumbent  detritus  has 
been  washed  off.  The  excavations  around  the  base  of  the  ridge  expose 
a  mass  of  strata  from  70  to  100  feet  high;  of  this,  twenty  feet  at  the 
bottom  are  chiefly  made  up  of  quartzose  sand  and  pebbles,  constituting 
the  pay-gravel.  Above  this  is  an  irregular  bed  of  lignite,  containing 
half  carbonized  trunks  of  trees,  with  much  pyrites  about  them,  showing 


THE  WESTERN  SLOPE - NEVADA  COUNTY. 


297 


the  reducing  power  of  the  organic  matter  in  its  decay.  Over  this, 
again,  is  a  heavy  mass  of  tine  gravels  and  sands,  the  latter  occasionally 
consolidated  into  sandstone,  the  whole  crowned  with  the  usual  beds  of 
pumice  and  ash,  with  the  solid  lava  at  the  summit.  This  range  of 
washings  extends  for  some  distance  to  the  east,  and  is  still  worked  to 
some  extent;  hut  apparently  not  now  so  energetically  as  in  former 
years. 

The  most  important  hydraulic  washings  in  the  county,  at  the  present 
time,  are  those  extending  along  its  northwestern  side,  close  by  and  pa¬ 
rallel  with  the  course  of  the  Middle  Yuba.  There  is  a  continuous  line  of 
claims  from  North  San  Juan  to  French  Corral,  a  distance  of  about 
eight  miles.  As  far  as  known  at  present,  we  are  inclined  to  connect 
this  deposit  of  gravel  with  the  chain  of  detrital  accumulations  coming 
down,  from  the  vicinity  of  Pilot  Peak,  through  Sierra  County,  and 
occupying  a  line  parallel  with  that  of  the  “Blue  Lead.”  But  this 
remains  to  be  demonstrated  by  a  careful  survey  and  map.  All  along 
the  Middle  Yuba,  from  San  Juan  west,  the  auriferous  detritus  occupies 
a  belt  somewhat  less  than  1000  feet  wide,  as  near  as  could  be  ascer¬ 
tained,  the  bottom  of  which  lies  at  an  elevation  of  about  1000  feet 
above  the  river  at  its  east  end,  falling,  however,  very  rapidly  as  it  is 
followed  down  the  valley.  It  seems  evident  that  the  present  river 
canon  has  been  entirely  excavated  since  the  detritus  was  deposited. 
The  materials  of  which  this  is  composed  are  almost  exclusively  pebbles 
and  boulders  of  granite  and  every  variety  of  metamorphic  rock  found 
in  the  Sierra,  together  with  many  of  quartz.  There  are  occasional 
beds  of  finer  gravels  and  sands,  rudely  stratified;  but  the  general  as¬ 
pect  of  the  mass  is  that  of  a  body  of  detritus  heaped  together  under  the 
influence  of  violent  and  rapidly  shifting  currents.  Near  the  surface 
the  oxidation  of  the  iron  has  given  the  gravel  the  usual  brownish-yel¬ 
low  color  imparted  by  decomposing  ferruginous  substances.  Lower 
down,  the  mass  has  often  a  bluish  color,  and  is  firmly  cemented  together 
by  pyrites,  which  consolidation  has  evidently  been  effected,  since  the 
deposition  of  the  gravel,  by  the  reducing  agency  of  the  organic  matter 
buried  in  the  deposit.  This  organic  matter,  through  the  region  in 
question,  seems  to  be  exclusively  of  vegetable  origin,  as  the  remains  of 
trees  are  found  everywhere,  while  we  examined  and  inquired  in  vain 


GEOL.  VOL.  T. — 38 


298 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


for  those  of  animals.  The  much  greater  frequency  of  the  remains  of 
animal  life  in  the  central  mining  districts  of  the  State  may  be  due  to 
climatic  causes;  the  conditions  appear  to  have  been  unfavorable  for 
the  spreading  of  the  mastodon  and  the  elephant  through  this  more 
northerly  region. 

All  considerations  and  facts  connected  with  the  yield  of  the  hydraulic 
washings  and  the  cost  of  the  process,  as  well  as  the  description  of  the 
elaborate  and  costly  system  of  “  ditches,”  or  canals,  by  which  the  water 
is  supplied  in  sufficient  quantity  for  these  very  extensive  operations, 
must  be  deferred  to  another  volume.  Before  anything  satisfactory  can 
be  published,  it  will  be  necessary  to  make  a  careful  instrumental  sur¬ 
vey  of  the  ground,  so  as  to  determine  approximately  how  many  cubic 
yards  have  been  removed  at  the  localities  which  are  to  be  described, 
this  being  the  fundamental  element  in  the  calculation,  and  one  in  regard 
to  which,  so  far  as  our  experience  goes,  no  reliable  information  can  be 
obtained  from  the  miners  themselves. 


Section  X, — Sierra  County. 

Sierra  County  is  an  exceedingly  rough  and  mountainous  district, 
high  up  in  the  mountains  and  furrowed  by  immense  canons.  It  is  of 
a  very  irregular  shape,  and  small  in  size  compared  with  many  of  the 
other  counties  in  the  State.  Its  southern  boundary  is  the  Middle 
Yuba,  and  its  northern  one  follows  the  very  irregularly  curving  water¬ 
shed  between  the  tributaries  of  the  Xortli  Yuba  and  the  Feather.  The 
extreme  eastern  portion  of  the  county,  or  that  which  lies  beyond  the 
crest  of  the  Sierra,  is  drained  by  a  branch  of  the  Truckee.  The  Xortli 
Yuba  runs  through  its  centre,  and  has  several  considerable  tributaries 
coming  in  from  the  north,  all  running  through  very  deep  and  narrow 
canons.  The  western  or  principal  minipg  portion  of  the  county  covers 
an  area  of  about  twentyffive  miles  square. 

Sierra  County  has  hardly  been  explored  at  all  by  the  Survey.  We 
have  passed  hastily  over  the  western  and  southern  portions  of  it,  and 
Mr.  Asliburner  examined,  in  1861,  the  principal  quartz-mines  then 
opened.  Since  that  time  the  county  has  been  highly  prosperous  ;  her 


THE  WESTERN  SLOPE  —  SIERRA  COUNTY. 


299 


quartz-mines  have  much  increased  in  number,  and  some  of  them  have 
been  highly  productive.  The  hydraulic  washings  are  also  of  great 
extent,  and  there  is  still  remaining  a  large  amount  of  auriferous  detritus 
to  he  worked  over  by  this  method.  The  county  has  suffered  by  its 
remoteness  from  the  centre  of  the  State  and  the  source  of  supplies;  but 
the  improvements  constantly  making,  especially  the  railroad  to  Marys¬ 
ville  and  Oroyille,  are  gradually  bringing  about  a  considerable  change 
in  this  respect. 

The  western  part  of  the  county  is  chiefly  occupied  by  the  auriferous 
slates,  where  these  have  not  been  covered  by  the  recent  volcanic  accu¬ 
mulations.  These  slates  were  seen  near  Camptonville,  where  they  have 
the  usual  northwest  strike  and  northeasterly  dip.  They  are  very  soft 
and  readily  undergo  decomposition.  A  dyke  of  granite,  from  ten  to 
thirty  feet  wide,  cuts  through  them  at  this  place,  and  both  it  and  the 
slates  have  been  much  softened  and  changed  by  chemical  agencies ;  but 
this  appears  to  have  been  effected  since  the  deposition  of  the  gravels 
and  volcanic  materials  upon  them,  and  not  to  be  the  result  of  the  intru¬ 
sion  of  the  granitic  mass. 

The  slates  are  seen  again  in  the  deep  canon  of  the  north  fork  of  the 
Yuba,  near  the  mouth  of  Cherokee  Creek,  and  also  at  Brandy  City,  a 
few  miles  farther  on  in  the  same  direction.  The  North  Yuba,  where 
the  west  line  of  the  county  cuts  it,  is  2166  feet  above  the  sea,  and  this  is 
probably  the  lowest  spot  within  the  county,  unless  it  be  the  bed  of  the 
Middle  Yuba,  for  a  small  portion  of  its  course  along  the  south  boun¬ 
dary.  The  rapid  rise  of  the  country  and  the  generally  great  elevation 
of  Sierra  County  may  be  inferred  from  the  fact  that  Brandy  City  is 
3592  feet  and  Eureka  5223  feet  above  the  sea-level.  All  along  this 
high  plateau  the  surface  is  covered  with  lava;  but  the  canons  which 
are  cut  in  it  everywhere  reveal  the  presence  of  the  underlying  slates. 

From  Eureka  to  Poker  Flat,  a  distance  of  nine  miles,  the  road  skirts 
along  high  volcanic  “  Buttes,”  which  cap  the  slates.  Some  of  these 
elevations  are  very  sharp;  but  there  is  one  which  is  a  lofty  table,  pro¬ 
bably  over  6500  feet  high,  and  very  conspicuous  through  that  region ; 
it  appears  to  be  a  bed  of  hard  basaltic  lava.  This  volcanic  range  lies 
along  the  crest  of  the  Sierra,  and  the  scenery  in  this  part  of  the  county 
is  very  grand.  One  peak  was  estimated  at  over  8000  feet  in  height,  or 


300 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


500  feet  higher  than  Pilot  Peak.  Most  of  the  lava  is  basaltic;  but 
there  is  a  large  amount  of  breccia,  or  volcanic  conglomerate.  At 
Deadwood,  the  trail  followed  by  our  party  again  descended  on  to  the 
slates,  and  between  them  and  Poker  Flat  large  masses  of  serpentine 
were  seen,  together  with  talcose-slate.  The  last-mentioned  place  lies 
in  the  deep  valley  of  Canon  Creek,  which  is  one  of  the  largest  branches 
of  the  North  Yuba.  From  here  to  Whiskey  Diggings,  close  by  the 
north  line  of  the  county,  the  slates  predominate,  with  occasional  masses 
of  serpentine  and  talcose-slate.  All  through  this  region,  however,  the 
higher  portions  of  the  country  are  covered  by  lava :  it  is  only  in  the 
valleys  and  canons  that  the  slates  are  seen.  Where  exposed,  these 
rocks  are  found  to  have  a  strike  more  nearly  approaching  a  north  and 
south  direction  than  is  usual  in  the  more  southern  portions  of  the  min¬ 
ing  region  ;  but  they  are  very  much  broken  and  twisted  about.  There 
are  also  many  quartz-veins  included  in  them,  although  none  of  these 
were  worked  at  the  time  of  our  visit  to  this  region. 

There  were,  however,  important  quartz-mines  above  Downieville, 
and  near  the  “  Buttes,”  as  they  are  called,*  which  were  examined,  in 
1861,  by  Mr.  Ashburner,  from  whose  notes  the  following  notice  of 
them  is  condensed. 

The  mines  in  question  are  situated  about  fourteen  miles  above  Dow¬ 
nieville,  and  high  up  on  the  side  of  the  Buttes,  within  1500  feet  of  their 
summit,  and  at  an  estimated  elevation  of  7000  feet  above  the  sea-level. 
In  1861  there  was  only  a  trail  above  Downieville,  which  was  then  much 
frequented  by  travellers  to  Washoe,  and  which  has  since  been  made 
into  a  rgad.  To  reach  the  mine  and  mill,  it  was  necessary  to  leave 
this  trail  at  the  base  of  the  mountain  and  climb  up  its  sides  to  an  ele¬ 
vation  of  some  2000  feet  above  the  river.  Here  the  outcrop  of  an 
immense  vein  is  seen,  which  can  be  traced  for  a  great  distance,  cutting 
across  ravines  and  gulches. 

On  this  vein,  and  working  the  quartz  obtained  from  it,  is  situated 
the  mill  of  the  “  Sierra  Buttes  Quartz  Mining  Company,”  as  also  that 
of  the  “  Independence  Company.”  The  vein  bears  nearly  east  and 

*  These  are  sometimes  designated  as  the  Sierra  Buttes,  hut,  more  frequently,  the  Dow¬ 
nieville  Buttes. 


THE  WESTERN  SLOPE - SIERRA  COUNTY. 


301 


west,  and  dips  to  the  north,  at  an  angle  of  42°.  It  is  inclosed  in  a  hard 
metamorphic  rock,  and  varies  from  six  to  thirty  feet  in  width.  Only 
the  richer  portions  of  the  quartz  are  passed  through  the  stamps,  and 
this  is  obtained  from  near  the  foot-wall  of  the  lode;  this  more  produc¬ 
tive  streak  varies  in  width  from  two  to  seventeen  feet,  and  the  aver¬ 
age  thickness  of  the  portion  worked  out  is  twelve  feet. 

The  mills  of  the  Sierra  Buttes  Company  are  two  in  number,  each 
having  twelve  stamps ;  they  are  worked  by  water-power,  the  water 
being  obtained  from  the  numerous  springs  which  issue  from  the  moun¬ 
tains.  One  of  them  was  built  in  1853  and  the  other  in  1856;  but 
quartz  was  worked  here  as  early  as  1851  by  means  of  arrastras.  These 
mills  crushed,  at  the  time  of  Mr.  Ashburner’s  visit,  an  average  of  900 
tons  of  quartz  per  month,  at  a  cost  per  ton  of  $1.35 ;  the  yield  was,  on 
the  average  of  the  two  years  1860-1,  $14.82  per  ton,  making  $20,000 
for  each  run  of  six  weeks  between  the  cleanings.  The  cost  of  extract¬ 
ing  the  quartz  and  delivering  it  at  the  mill  being  reckoned  at  $5.87  per 
ton,  it  will  not  be  difficult  to  perceive  that  this  mine  is  one  of  the  most 
valuable  pieces  of  property  in  the  State,  especially  as  the  moderate  per¬ 
centage  of  gold  in  the  quartz  indicates  a  permanently  productive  mine. 

The  Independence  Mine  is  on  the  same  vein  as  the  one  just  described. 
The  portion  of  the  lode  which  is  worked  is  from  three  to  nine  feet  in 
thickness.  The  average  yield  of  the  quartz  was,  in  1861,  $15  a  ton, 
and  the  expense  of  extraction  $5 ;  that  of  treating  the  quartz  at  the 
mill  was  $2.89.  The  mill  had  twelve  stamps;  but  another  of  the  same 
size  was  erecting  at  that  time. 

'  Mr.  Asliburner,  in  his  notes,  under  date  of  1861,  speaks  very  highly 
of  Sierra  County  as  a  quartz-mining  region,  and  it  would  appear  that 
events  have  proved  the  justice  of  his  remarks.  Quite  a  number  of 
important  lodes  have  been  opened  in  that  region  and  have  been  suc¬ 
cessfully  worked,  as  is  reported  on  good  authority;  but  we  have  no 
details  of  their  location  or  of  the  capacity  of  the  mills  which  have  been 
erected. 

Few  counties  in  the  State  are  so  thoroughly  covered  by  beds  of  vol¬ 
canic  origin  as  is  Sierra.  The  whole  region  west  of  the  crest  of  the 
mountains  seems  to  be  everywhere  overlain  by  these  deposits,  except¬ 
ing  in  and  near  the  river  valleys  and  canons,  which,  as  before  remarked, 


302 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


are  cut  down  to  an  immense  depth  in  the  underlying  slates.  The  vol¬ 
canic  formations  seem,  wherever  examined,  to  cover  vast  accumula¬ 
tions  of  auriferous  detritus,  which  are  extensively  worked  at  a  great 

* 

number  of  points.  It  must  not  be  inferred,  however,  that  these  beds 
of  gravel  are  scattered  uniformly  over  the  surface,  or  deposited  in  one 
great  sheet,  as  would  be  the  case  if  they  had  been  formed  along  an 
ocean  shore,  or  had  assumed  their  present  position  under  the  influence 
of  marine  currents.  On  the  contrary,  nothing  can  be  clearer  than  that 
these  accumulations  of  detritus  have  been  formed  by  torrents  of  fresh 
water  tearing  down  the  sides  of  the  mountains,  and  sometimes  giving 
rise  to  extensive  rivers,  of  which  the  former  courses  may  now  be  traced 
across  canons  thousands  of  feet  deep ;  while  in  other  cases  the  torrential 
flows  have  been  of  limited  extent,  and  have  not  borne  the  detritus  with 
which  they  were  charged  to  any  great  extent  from  its  source. 

We  could,  at  the  present  time,  give  some  idea  of  the  physical  condi¬ 
tions  which  must  have  prevailed  in  the  Sierra,  at  the  time  these  re¬ 
markable  phenomena  were  exhibiting  themselves;  but  there  are  many 
points  on  which  more  light  must  be  thrown  by  a  minute  examination 
of  the  region,  and  what  we  especially  need  is  a  map  of  the  Gold  Region, 
with  sections  across  the  formations  from  actual  surveys,  without  which 
it  will  be  impossible  to  give  any  intelligible  view  of  the  geological 
order  of  events,  and  of  the  gigantic  scale  on  which  causes,  not  very 
different  in  their  nature  from  those  now  operating  in  the  Sierra,  were, 
in  former  times,  moulding  the  country  into  its  present  condition,  and 
storing  away  those  vast  deposits  of  auriferous  material  which  can  be 
drawn  upon  for  so  long  a  time  without  fear  of  their  being  exhausted. 

The  famous  “Blue  Lead”  of  Sierra  County,  although  only  examined 
by  us  at  one  or  two  points,  so  that  we  are  unable  to  give  any  connected 
description  of  it  from  our  own  knowledge,  should  not  be  omitted  in 
this  imperfect  sketch  of  the  geology  of  this  part  of  the  State.  It  has 
been  well  described  by  Mr.  C.  S.  Capp  in  the  “  Evening  Bulletin”  of 
San  Francisco,*  and  the  facts  will  there  be  found  clearly  set  forth  which 
have  long  since  led  the  intelligent  miners  of  California  to  a  clear  under- 


*  Quoted  in  Hittell’s  “  Handbook  of  Mining  for  the  Pacific  States;”  see  page  72. 


THE  WESTERN  SLOPE - SIERRA  COUNTY. 


303 


standing  of  the  origin  of  this,  as  well  as  of  the  many  other  ancient 
river  channels  in  the  mining  region. 

The  course  of  this  channel  of  detritus,  as  appears  from  a  sketch 
kindly  furnished  the  Survey  by  Mr.  George  Black,  of  San  Francisco, 
who  has  superintended  the  construction  of  some  of  the  most  important 
ditches  in  this  region,  was  nearly  north  and  south,  and  it  has  been  dis¬ 
tinctly  traced  from  Sebastopol,  in  the  northern  part  of  Sierra,  quite 
across  into  Nevada  County,  to  Snow  Point,  on  the  south  side  of  the 
Middle  Yuba,  a  distance  of  between  twenty  and  twenty-five  miles. 
The  principal  points  where  it  is  worked,  between  these  two  places,  are 
Monte  Cristo,  City  of  Six,  Bock  Creek,  Forest  City,  Wet  Ravine, 
Smith’s  Flat,  Chip’s  Flat,  and  Minnesota.  The  phenomena  of  the 
“  Blue  Lead”  do  not  differ  materially  from  those  exhibited  by  the 
auriferous  deposits  under  the  Table  Mountain  of  Tuolumne  County, 
which  have  already  been  noticed.  All  the  most  striking  facts  of  the 
one  are  repeated  in  the  other ;  but  the  course  of  the  ancient  river  of 
Tuolumne  was  nearly  coincident  with  that  of  the  present  ones,  so  that 
it  has  only  been  cut  through  in  one  place  by  a  very  deep  canon,  while 
the  “  Blue  Lead”  ran  nearly  at  right-angles  to  the  rivers  now  existing 
in  Sierra  County,  and  consequently  its  continuity  has  been  repeatedly 
broken.  Moreover,  while  the  valley  of  Table  Mountain  River  is  clearly 
seen  to  have  been  filled  up  with  one  flow  of  lava  from  the  High  Sierra, 
so  numerous  and  complicated  were  the  volcanic  phenomena  in  the 
northern  portion  of  the  Sierra,  that  it  would  not  be  easy  to  say,  with¬ 
out  a  careful  examination  of  the  region,  that  the  obliteration  of  the 
“  Blue  Lead”  may  not  have  been  the  result  of  several  successive  erup¬ 
tions,  or  even  a  long-continued  series  of  volcanic  outbreaks. 

From  what  has  been  seen  of  the  geology  of  the  region  east  of  the 
crest  of  the  Sierra,  the  predominance  of  volcanic  formations  .in  that 
region  is  inferred.  Large  deposits  of  a  sedimentary  material  of  fresh¬ 
water  origin  and  a  later  Tertiary  age  are  believed  to  occur  in  some  of 
the  valleys,  and  these  have  been  often  reported  in  the  newspapers  as 
containing  beds  of  coal.  This  may  very  possibly  be  the  case,  although 
it  is  not  likely  that  they  will  be  found  to  be  very  extensive.  Of  the 
many  seams  of  lignite  and  half-formed  coal  which  have  been  noticed 


304 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


by  us  in  these  fresh-water  Tertiary  beds,  on  the  east  slope  of  the  Sierra, 
none  have  yet  been  observed  of  any  considerable  magnitude. 


Section  XI. — Plumas  County. 

The  few  observations  which  our  time  and  means  have  allowed  us  to 
make  in  the  counties  of  Yuba  and  Butte  have  already  been  given  in 
Chapter  VIII,  and  we  pass  on,  therefore,  to  the  next  county  north  of 
Sierra,  namely,  Plumas. 

This  county  is  very  much  larger  than  those  to  the  south  along  the 
auriferous  belt;  it  is  fully  fifty  miles  across  it  from  north  to  south,  and 
about  seventy-five  in  the  opposite  direction.  It  comprises  the  whole 
region  drained  by  the  Upper  Feather  River  and  its  affluents.  This 
river  has  two  principal  forks,  the  north  and  middle ;  the  south  fork 
being  of  very  insignificant  size  compared  with  the  others.  The  middle 
fork  rises  on  the  east  side  of  the  crest  of  the  Sierra,  and  has  cut  its 
way  through  it,  flowing  down  one  of  the  deepest  and  grandest  canons 
in  the  State.  Its  course  is  in  a  series  of  zigzags,  alternately  flowing  in 
directions  parallel  with,  and  at  right-angles  to,  the  trend  of  the  moun¬ 
tain  ranges  which  make  up  the  great  chain  of  the  Sierra  in  this  region. 
The  main  branch  of  the  north  fork  of  the  Feather  rises  on  the  south 
slope  of  Lassen’s  Peak,  and  its  chief  tributary,  Spanish  Creek,  heads 
on  the  southwest  side  of  a  lofty  range  of  mountains  which  lies  parallel 
with  the  main  ridge  of  the  Sierra,  and  extends  along  the  west  side  of 
Iloney  Lake  Valley.  This  lake  is  an  independent  basin,  like  so  many 
others  on  that  side  of  the  Sierra,  and  it  receives  two  principal  streams, 
one  coming  in  from  the  south  and  heading  near  Beckworth’s  Pass;  the 
other  from  the  north  and  having  its  source  in  the  vicinity  of  Xoble’s 
Pass. 

The  above-named  two  passes  are  the  principal  ones  crossing  the 
mountains  and  leading  to  the  eastern  side  of  Plumas  County,  and 
much  discussion  has  been  carried  on,  in  the  newspapers,  as  to  their 
comparative  feasibility  for  railroad  purposes,  it  having  been  claimed  by 
the  residents  in  this  part  of  the  State  that  the  route  following  up  the 
canon  of  the  Middle  Feather,  and  crossing  by  Beckworth’s  Pass,  was 


THE  WESTERN  SLOPE  —  PLUMAS  COUNTV. 


305 


lower  than  any  other  north  of  Walker’s  Pass,  and  that  it  presented 
great  advantages  on  account  of  the  small  body  of  snow  which  lies  here 
during  the  winter.  For  an  account  of  the  exploration  of  the  region 
around  Noble’s  Pass,  and  the  northern  portion  of  Plumas  County  in 
general,  reference  may  be  made  to  Lieutenant  Beckwith’s  examina¬ 
tions,  in  Volume  II  of  the  Pacific  Railroad  Reports.  It  does  not  appear 
that  the  Beckworth  route  lias  ever  been  instru  men  tally  explored,  and 
we  are  unable  to  state  the  height  of  the  pass ;  that  of  Beckworth’s 
house,  at  the  junction  of  the  branch  of  that  name  with  the  main  stream 
is  given  by  Goddard  at  4570  feet.  The  altitude  of  Noble’s  Pass  is 
given  by  Lieutenant  Beckwith  at  6074  feet. 

The  main  crest  of  the  Sierra,  or  that  on  which  the  highest  peaks  are 
situated,  is  near  the  western  side  of  the  county,  the  most  prominent 
elevations  being  Pilot  Peak,  Spanish  Peak,  and  Lassen’s  Peak,  which 
latter  is  the  most  northwestern  point  of  Plumas,  and  is  where  that 
county  corners  with  Tehama  and  Shasta. 

The  valleys  between  the  mountain  ranges,  in  the  western  part  of  the 
State,  are  very  narrow,  and  occupy  but  an  insignificant  proportion  of 
the  surface,  as  compared  with  the  mighty  masses  of  the  mountains 
themselves.  Iloney  Lake  Valley,  however,  comprises  quite  an  exten¬ 
sive  area,  being  about  sixty  miles  long  from  east  to  west,  and  from  fif¬ 
teen  to  twenty  miles  across  in  the  opposite  direction.  According  to 
Mr.  J.  F.  Kidder,  engineer  in  charge  of  the  Boundary  Survey  from 
Lake  Bigler  north,  this  valley,  from  the  head  of  the  lake  eastward,  is 
dry  and  barren  and  destitute  of  vegetation,  excepting  sage-brush  and 
grease-wood.  But,  near  the  Sierra,  on  the  west  and  southwest  of  the 
lake,  and  also  on  Susan  River,  which  empties  into  it  from  the  north, 
are  excellent  farming  lands,  under  cultivation,  while  the  mountains 
around  are  well  supplied  with  good  timber.  Considerable  business  is 
done  here  in  raising  supplies  and  sawing  lumber  for  the  mines  in  the 
adjoining  State  of  Nevada. 

Some  explorations  were  made  in  Plumas  County,  in  1861,  by  Mr. 
Ashburner,  and  Messrs.  Brewer  and  King  passed  through  the  central 
and  northwestern  portion  of  it  in  1863,  while  engaged  in  a  reconnais¬ 
sance  of  the  northern  part  of  the  State;  from  their  notes  most  of  what 
follows  in  regard  to  the  geology  of  the  county  is  taken. 


GF.OT,.  VOL.  T. — 39 


30  G 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


The  party  entered  Plumas  from  the  south,  passing  over  the  trail 
from  Poker  Flat,  in  Sierra  County,  to  Quincy,  the  county-seat.  All 
through  the  region  between  Poker  Flat  and  Whiskey  Diggings  the 
rocks  exposed  in  the  canons  are  slates,  with  some  heavy  masses  of  ser¬ 
pentine  included  among  them ;  all  the  higher  parts  of  the  country  are 
covered  with  immense  accumulations  of  lava. 

Pilot  Peak,  which  is  near  the  southern  line  of  the  county,  is  an  iso¬ 
lated,  volcanic  knob  of  hard,  ash-gray,  crystalline  basaltic  rock,  which 
is  most  beautifully  columnar  on  its  northern  slope.  The  view  from  the 
summit  is  peculiarly  tine,  Lassen’s  Peak  being  visible  in  the  northwest, 
and  the  Coast  Ranges  in  the  southwest.  Fifteen  or  twenty  miles  to 
the  northeast,  mountains  are  seen  which  are  of  about  the  same  height 
as  Pilot  Peak,  and  very  deeply  eroded  on  all  sides;  indeed,  the  whole 
region  to  the  east  and  northeast  is  furrowed  by  tremendous  canons, 
many  of  them  being  over  2000  feet  deep.  In  the  southeast  the  Dow- 
nieville  Buttes  were  seen,  with  a  very  rugged  outline.  The  most  ele¬ 
vated  points  in  the  range  lie  to  the  east  of  the  line  connecting  Pilot 
Peak  and  the  Downieville  Buttes ;  the  highest  of  these  is  perhaps  500 
feet  higher  than  Pilot  Peak  itself;  Table  Mountain,  already  mentioned, 
lies  to  the  west,  and  is  nearly  as  high.  The  whole  region  to  the  south 
of  the  summit  is  extremely  rough,  and  its  sky  outline  very  serrated. 
On  the  peak,  the  magnetic  needle  is  very  irregular,  and  was  observed 
to  he  directed  towards  nearly  every  point  within  the  space  of  a  few 
square  rods.  The  elevation  of  Pilot  Peak  above  the  sea  is  7605  feet, 
and  of  this  the  upper  portion  is  exclusively  volcanic;  the  lava  forming 
a  mass  about  650  feet  thick,  as  estimated  from  observations  taken  at 
Onion  Valley,  1216  feet  below  the  summit  of  the  peak. 

The  auriferous  slates  are  very  finely  exposed  on  the  north  side  of  the 
mountain,  having  a  north  and  south  strike,  and  a  dip  to  the  east  of 
about  80° ;  they  are  cut  squarely  off  at  the  top  and  covered  with  lava. 
The  strike  of  the  slates,  however,  is  not  uniform  in  this  region.  One 
mile  northeast  of  Onion  Valley,  large  ^masses  were  observed  with  a 
trend  of  Y.  35°  W.,  and  a  southwesterly  dip;  and  again,  on  descending 
into  the  canon  of  the  Middle  Yuba,  they  were  seen  running  FT.  15°  W., 
and  from  that  to  Y.  35°  W.,  and  standing  nearly  vertical.  Great  masses 
of  serpentine  occur  along  the  trail  between  Pilot  Peak  and  Onion 


THE  WESTERN  SLOPE - PLUMAS  COUNTY. 


307 


Valley,  and  between  this  and  Nelson’s  Point  a  variety  of  magnesian 
rocks  were  noticed. 

The  canon  of  the  Middle  Yuba  is  exceedingly  deep,  the  difference 
of  level  between  the  river  at  Nelson’s  Point  and  the  summit  of  Pilot 
Peak  being  fully  3650  feet.  From  the  bottom  of  the  canon  to  the  top 
of  the  slates,  the  vertical  height  is  not  less  than  3000  feet,  all  of  which 
has  been  removed,  by  the  agency  of  water,  since  the  time  of  the  erup¬ 
tion  of  the  overlying  volcanic  materials.  Nowhere  in  the  Sierras  do 
we  find  more  stupendous  examples  of  denudation  than  occur  in  the 
region  north  and  northeast  of  Pilot  Peak,  in  the  canons  of  the  Middle 
Yuba  and  its  branches.  At  Nelson’s  Point,  the  slates  stand  nearly 
vertical,  and  crop  out  in  grand  masses  along  the  sides  of  the  canon. 
But  on  the  steep  slopes,  on  both  sides,  the  surface  strata  often  curve, 
as  if  bent  by  sliding  down  the  hill,  so  as  to  give  the  impression  of  a 
dip  to  the  east,  when  in  fact  they  stand  perfectly  vertical  below.  The 
elevation  of  Nelson’s  Point  above  the  sea  is  3858  feet. 

The  basin,  called  the  American  Valley,  in  which  the  town  of  Quincy 
is  situated,  is  about  eleven  miles  long  and  from  two  to  three  wide ;  it 
has  an  elevation  of  3500  feet  above  the  sea.  In  the  range  of  mountains 
which  was  crossed  in  going  from  Quincy  to  Elizabethtown,  and  which 
is  about  eight  miles  wide,  slates  and  sandstones  were  observed,  some¬ 
times  but  little  metamorphosed.  They  had  the  usual  northwest  strike, 
but  dipped  towards  the  southwest.  These  slates  are  capped,  at  the 
summit  of  the  range,  by  hard  lava,  which  occupies  only  a  narrow  belt, 
the  fianks  of  the  mountain  on  the  north  side  being  of  metamorphic 
rocks,  similar  to  those  seen  on  the  south.  Some  granitic  masses  occur 
in  this  region.  A  bold  and  elevated  ridge  of  this  rock  was  seen  a  few 
miles  west  of  Quincy,  and  again,  about  two  miles  before  reaching  Eliz¬ 
abethtown,  where  it  occupies  a  belt  about  a  mile  in  width.  The  slates, 
however,  are  the  predominating  formation.  This  part  of  the  county  is 
principally  occupied  by  the  metamorphic  rocks  over  an  area  of  about 
thirty  miles  in  diameter ;  but  this  is  almost  entirely  surrounded  by  vol¬ 
canic  materials,  the  great  lava  streams  which  have  come  down  from 
Lassen’s  Peak  on  the  north,  and  Pilot  Peak  on  the  south,  uniting  with 
the  volcanic  crest  of  the  Sierra,  so  as  to  cover  the  slates  around  three- 
cpiarters  of  the  circumference  of  the  circle. 


308 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


From  Indian  Valley  the  route  followed  led  up  to  Genesee  Valley, 
following  Genesee  Creek,  a  branch  of  Spanish  Creek.  This  stream 
runs  nearly  west,  through  a  canon,  which  a  few  miles  higher  up  opens 
out  into  a  valley  about  four  miles  long  and  three-fourths  of  a  mile 
broad;  the  upper  part  of  this  is  occupied  by  granitic  rocks,  the  lower 
by  slates.  In  the  canon,  about  a  mile  and  a  half  from  its  mouth, 
Messrs.  Brewer  and  King  discovered  a  locality  of  fossils,  where  a  con¬ 
siderable  number  of  specimens  of  various  genera  and  species  were 
obtained.  They  were  found  principally  on  the  spurs  of  rock  coming 
down  from  the  north  and  in  the  canons  between  them.  The  rock  is  a 
metamorphic  sandstone,  rather  tine-grained,  and  portions  of  it  are  of  a 
deep-red  color,  resembling  in  appearance  much  of  the  Old  Red,  or 
Devonian  sandstone  in  England  and  on  the  Continent.  In  places  it  is 
so  much  changed  that  the  fossils  have  become  nearly  or  even  quite 
obliterated ;  but  a  number  of  species  were  obtained  in  a  sufficiently 
good  state  of  preservation  to  be  determined.  The  specimens  collected 
here  were  referred  to  Mr.  Meek  for  examination,  and  were  considered 
by  him  to  be  almost  certainly  of  Jurassic  age;  they  have  been  described 
by  him  in  Section  III  of  the  first  volume  of  the  Palaeontology  of  this 
Report,  and  are  figured  in  plates  7  and  8  of  that  volume.*  The  strata 
in  which  the  fossils  were  found  have  a  trend  varying  from  east  and 
west  to  northeast  and  southwest,  and  they  dip  to  the  south  at  all  angles 
between  30°  and  80°.  This  locality  is  about  four  miles  below  Gifford’s 
Ranch,  and  near  a  small  grassy  flat  into  which  the  canon  opens,  and 
which  is  called  Mormon  Station. 

Above  this  the  valley  contracts  again  into  a  narrow  canon ;  but  two 

miles  farther  up  it  opens  into  another  and  larger  basin,  called  Genesee 

Valley.  Along  the  ravine,  the  rocks  are  highly  metamorphosed,  and 

their  stratification  is  much  disturbed.  It  is  in  this  valley  that  Gifford’s 

Ranch  is  situated,  and  near  it  is  the  junction  of  the  granitic  and  meta- 
• 

morphic  rocks.  Kear  the  line  of  contact  of  the  two  formations,  is  a 
belt  of  limestone  which  is  highly  crystalline,  but  contains  a  few  obscure 
fossils,  apparently  the  fragments  of  stems  of  crinoids,  and  which  are 


*  For  some  notes  by  Mr.  Meek  on  the  relations  and  affinities  of  the  fossils  found  at 
this  locality,  see  the  Appendix  to  this  volume. 


THE  WESTERN  SLOPE  —  PLUMAS  COUNTY. 


309 


probably  of  Carboniferous  age,  although  this  question  could  not  he 
definitely  settled. 

At  one  locality  between  the  main  belt  of  limestone  and  the  granite, 
where  there  is  a  curve  in  the  strata,  there  is  a  limited  patch  of  calcare¬ 
ous  slates  containing  quite  a  number  of  fossils,  some  of  them  in  very 
good  preservation.  These  fossils  belong  to  the  Triassic  series,  and 
prove  clearly  the  existence  at  this  point  of  the  same  formation  which  is 
so  well  developed  in  the  Humboldt  mining  region  in  Nevada,  and  also 
at  Washoe,  and  which,  as  we  have  abundant  evidence  to  prove,  extends 
over  a  vast  area  on  the  Pacific  coast.  Among  the  species  recognized  by 
Mr.  Gabb  as  occurring  here,  are  Ammonites  Ramsaueri? ,  Avicula  macro- 
nata,  Halobia  dnbia ,  Monotis  subcircular  is,  Myojphoria  alia  ?,  and  Pecten 
deformis .  * 

We  have  strong  reasons  for  believing  that  a  large  portion  of  the 
auriferous  slates  belong  to  the  same  formation  with  these  of  Genesee 
Valley,  which  are  themselves  worked  for  gold,  there  being  placers  all 
along  the  range  on  the  south  side  of  the  creek  quite  up  to  the  locality 
in  question. 

The  stratification  is  so  broken  in  this  region,  and  the  rock  so  much 
disturbed  and  metamorphosed,  that  it  would  require  a  much  longer 
time  than  our  party  were  able  to  give  to  it,  before  the  relative  position 
of  the  different  bodies  of  strata  could  be  made  out ;  the  district,  how¬ 
ever,  demands  a  most  thorough  examination. 

Some  localities  of  rich  copper  ores  have  been  discovered  about 
Genesee  Valley,  and  very  fine  specimens  of  vitreous  copper,  containing 
$200  of  silver  to  the  ton,  were  obtained  from  a  mine  in  that  neighbor¬ 
hood,  the  exact  position  of  which  we  are  unable  to  give.  Our  party 
visited  two  localities  where  mining  was  going  on.  One  was  the  Cos¬ 
mopolitan  Mine,  three-fourths  of  a  mile  from  Gifford’s  Ranch.  The 
vein  at  this  place  lies  between  the  limestone  and  the  granite,  having  a 
direction  of  about  N.  25°  W.  The  width  of  the  lode,  as  exposed  in  a 
shaft  a  few  feet  deep,  was  about  twelve  feet.  The  ore  is  a  mixture  of 
copper  pyrites  and  iron  pyrites. 


*  For  descriptions  of  these  fossils,  see  Section  II  of  Palaeontology  of  California,  Vol.  I  ; 
they  are  figured  on  plates  3  to  6. 


310 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


It  is  evident  that,  for  the  present,  copper-mining  labors  under  great 
disadvantages  in  this  region,  from  its  remoteness,  and  the  consequent 
cost  of  getting  supplies  and  of  conveying  the  ore  or  metal  to  a  market. 

From  Genesee  Valley,  our  party  returned  to  Indian  Valley,  and 
thence  made  their  way  in  a  westerly  direction  to  the  Big  Meadows,  in 
order  to  explore  the  vicinity  of  Lassen’s  Peak,*  and  to  seek  out  a  route 
to  its  summit.  Indian  V alley  is  from  ten  to  twelve  miles  long  and  is 
a  fertile  and  pleasant  spot,  although  its  elevation  is  considerable.  It  is 
quite  surrounded  by  high  mountains,  those  on  the  east  having  an  ele¬ 
vation  of  about  6000  feet.  In  passing  down  the  valley,  the  slates 
which  are  seen  on  the  east  side  were  observed  to  contain  more  jasper 
than  is  usual  in  the  Sierra. 

Between  Indian  Valley  and  the  Big  Meadows,  the  edge  of  the  great 
volcanic  region  is  struck ;  from  here  the  mass  of  lava  extends  almost 
uninterruptedly  to  the  Oregon  line  and  far  beyond.  The  Big  Mea¬ 
dows  are  on  the  north  fork  of  the  Feather  River,  and  form  a  delightful 
valley  about  fifteen  miles  long  and  from  two  to  three  wide ;  it  is  quite 
surrounded  by  volcanic  tables  and  ridges,  those  on  the  east  side  having 
an  elevation  of  about  500  feet  above  the  valley,  which  is  itself  4564 
feet  above  the  sea.  This  elevation  was  taken  at  the  lower  end  of  the  « 

valley,  near  Bidwell’s  store,  and  where  the  Chico  road  crosses. 

All  the  pebbles  seen  about  here  were  of  volcanic  rock;  but  the  meta- 
morphic  slates  are  reported  to  occur  at  Mountain  Meadows,  which  is  a 
basin  similar  to  the  Big  Meadows,  and  about  fifteen  miles  farther  to 
the  northeast.  The  soil  of  this  valley  is  rather  sandy,  especially  to¬ 
wards  its  upper  end,  and  the  elevation  is  too  great  for  any  other  agri¬ 
cultural  occupation  than  that  of  pasturing  cattle.  The  views  of  Las¬ 
sen’s  Peak  rising  above  the  upper  end  of  the  Big  Meadows,  are  pecu¬ 
liarly  grand.  The  mountain  does  not  show  so  distinct  a  conical  shape 


*  This  is  the  volcanic  mass  designated  as  Mount  St.  Joseph  on  the  Pacific  Railroad 
Maps ;  hut  it  is  universally  known,  in  California,  as  Lassen’s  Butte,  or  Peak ;  we  prefer 
the  English  word,  especially  as  the  French  one  is  not  properly  used,  when  applied  to  a 
high  mountain.  A  “butte,”  according  to  the  dictionary  of  the  French  Academy,  is  a 
“  petite  elevation  de  terre,”  or  a  “petit  tertre;”  “  knoll”  would  he  the  exact  translation 
of  it. 


TIIE  WESTERN  SLOPE - PLUMAS  COUNTY. 


311 


when  seen  from  this  direction,  as  it  does  from  others;  but  its  slopes  are 
very  steep,  especially  the  eastern  one. 

From  the  head  of  the  Big  Meadows,  Lassen’s  Peak  is  not  over  fif¬ 
teen  miles  distant  in  a  direct  line ;  but  by  any  practicable  route  it  is  fully 
twenty-five.  Our  party  followed  up  the  lied  Bluff  road  to  Loveless’s 
Ranch,  and  then  struck  through  the  forests  without  a  trail,  ascending 
gradually  over  a  volcanic  table,  the  surface  of  which  had  some  large 
rounded  boulders  of  lava  scattered  over  it:  but  which  was,  in  general, 
covered  by  a  deep  soil  of  a  dark-red  color,  formed  from  the  decompos¬ 
ing  basaltic  rock,  and  supporting  a  heavy  growth  of  timber,  Pinus  con- 
torta  being  the  most  abundant  tree.  In  this  lava  table  the  branches  of 
the  north  fork  of  the  Feather  have  cut  many  deep  canons. 

A  few  miles  southeast  of  the  peak,  there  are  several  hot  springs,  and 
indications  of  the  existence  of  others,  from  which  cold  water  is  now 
issuing.  One  of  these  is  called  “  Steamboat  Spring,”  and  from  this 
there  is  a  copious  flow  of  boiling  water,  while  steam  escapes  from  a 
great  number  of  vents,  scattered  over  an  area  of  two  or  three  acres. 
The  lava  has  been  very  extensively  decomposed  by  the  action  of  the 
hot  water,  which  dissolves  out  a  portion  of  the  silica,  and  leaves  a  mass 
of  clay,  either  white  or  colored,  according  to  the  amount  of  iron  in  the 
rock.  Portions,  which  are  now  quite  soft,  still  retain  perfectly  the  ori¬ 
ginal  structure  of  the  mass.  In  one  place,  a  large  amount  of  steam 
issues  in  a  pool  of  hot  water,  throwing  it  up  in  jets  to  the  height  of 
several  feet,  with  considerable  noise.  Hunters  say  that  they  have  seen 
the  water  raised  as  high  as  twenty-five  feet,  but  at  the  time  of  the  visit 
of  our  party  the  jets  did  not  exceed  eight  feet  in  elevation. 

Northwest  of  the  locality  just  noticed,  about  two  miles  from  it,  and 
eight  miles  from  the  summit  of  the  peak,  in  a  direction  N.  70°  E., 
magnetic,  is  the  so-called  “  Boiling  Lake.”  This  is  a  pool  of  hot  water, 
about  600  feet  long  and  300  wide ;  it  lies  in  a  depression  between  two 
streams  of  lava,  the  banks  rising  to  the  height  of  a  hundred  feet  around 
it,  except  on  the  side  of  the  mountain,  where  it  has  an  outlet  of  a  foot 
or  two  in  width.  The  same  decomposition  of  the  lava  has  gone  on 
around  this  lake  which  was  noticed  above  as  having  taken  place  at  the 
Steamboat  Spring.  The  water  is  whitened  with  the  clayey  material, 
and,  in  some  places,  is  thickened  to  the  consistency  of  cream.  Steam 


312 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


jets  issue  from  this  viscous  material,  and  along  the  banks  and  around 
them  the  clay  accumulates,  so  as  to  form  tubes,  or  miniature  mud-vol¬ 
canoes,  from  a  few  inches  to  four  feet  in  height.  At  the  upper  end  of 
the  pool,  clouds  of  steam  and  sulphurous  gases  rise  from  crevices  in  the 
lava,  which  is  slowly  slaking  and  wasting  away  under  tlieir  influence, 
the  rocks  being  covered  with  deliquescent  salts,  especially  the  sulphate 
of  iron,  which  by  its  decomposition  gives  to  the  clays  a  variety  of 
shades  of  red,  pink,  purple,  and  brown.  The  elevation  of  this  place  is 
5976  feet  above  the  sea. 

About  four  miles  northwest  of  the  Boiling  Lake  are  other  hot  springs, 
which  are  much  more  copious  than  at  either  of  the  localities  already 
described,  and  where  the  decomposition  of  the  rocks  has  taken  place  on 
a  most  extensive  scale.  These  springs  are  scattered  along  a  canon  for 
half  a  mile,  and  they  are  copious  enough  to  form  quite  a  stream,  which, 
in  its  downward  course,  bears  away  the  decomposed  materials  con¬ 
stantly  falling  into  it  from  the  sides  of  the  adjacent  cliffs.  Sulphur  is 
sublimed  from  many  of  the  cavities,  forming  the  most  delicate  and 
beautiful  crystallizations  on  the  surrounding  rocks.  The  same  highly- 
colored  clays  and  saline  incrustations  occur  here  which  were  described 
as  existing  at  the  other  localities.  In  all  of  these  hot  springs  the  Pani- 
cum  thermale  and  a  low  form  of  vegetation,  supposed  to  be  Nostoc ,  are 
found  growing  in  and  about  the  hot  water  and  in  places  exposed  to  the 
jets  of  steam,  exactly  as  at  the  Geysers,  which  have  been  already  de¬ 
scribed. 

From  the  last-mentioned  hot  spring,  the  land  rises  rapidly  towards 
the  north,  and  a  greater  variety  of  rocks  begins  to  be  noticed.  About 
four  miles  south  of  the  summit,  beds  of  volcanic  material,  having  a 
decidedly  slaty  structure  (rhyolite?)  were  observed.  Ascending  to  a 
height  of  about  1000  feet  above  the  hot  springs,  at  about  7000  feet 
above  the  sea,  the  vegetation  changed  and  assumed  the  peculiar  char¬ 
acter  which  it  has  in  the  High  Sierra ;  Abies  Williamsoni ,  Pinus  Bal- 
fouriana,  with  here  and  there  a  Picea,  were  the  principal  trees  in  the 
neighborhood  of  the  camp,  which  was  established  for  several  days,  at 
an  altitude  of  7596  feet,  while  the  party  was  engaged  in  examining  the 
summit  of  the  mountain. 

From  this  camp  (No.  149)  two  ascents  of  the  peak  were  made  by 


THE  WESTERN  SLOPE  —  PLUMAS  COUNTY. 


313 


M  essrs.  Brewer  and  King;  one  September  26,  1863,  the  other  on  the 
night  of  the  29th.  That  on  the  tirst  day  was  not  satisfactory,  as  a 
dense  cloud  of  dust  and  smoke  hung  over  the  Sacramento  Valley,  and 
obscured  the  neighboring  mountains.  At  the  time  of  the  second 
ascent,  the  weather  was  perfectly  clear,  a  light  rain  having  fallen  in  the 
valleys,  and  snow  on  the  mountain  tops.  The  camp  was  left  at  2  a.m., 
and  the  summit  reached  before  sunrise.  The  view  is  described  as  one 
of  unsurpassed  grandeur,  the  field  embraced  within  the  scope  of  vision 
extending  from  Mount  Hamilton  on  the  south  to  Mount  Pitt  on  the 

O 

north,  a  distance  of  about  340  miles  in  a  straight  line.  Along  the  line 
of  the  Sierra  to  the  south,  the  whole  chain  could  be  distinctly  seen, 
as  far  as  Pyramid  Peak.  East  and  west  the  field  was  more  contracted, 
extending  from  the  Coast  Ranges,  west  of  the  Sacramento  River,  to  the 
mountains  near  Pyramid  Lake. 

There  are  four  distinct  summits  to  the  peak,  the  highest  of  which  is 
10,577  feet  above  the  sea.  Three  of  these  points  are  quite  conspicu¬ 
ous  ;  the  other  is  less  so.  These  rise  to  the  height  of  from  250  to  350 
feet  above  the  depression  or  cavity,  which  was  undoubtedly  once  the 
crater  of  the  volcano,  the  rim  of  which  has  gradually  been  denuded  so 
as  to  leave  only  these  fragmentary  evidences  of  its  former  existence. 
The  western  point  shows,  in  a  very  marked  manner,  the  action  of 
steam  and  sulphurous  gases  upon  it,  as  it  is  much  whitened  and  decom¬ 
posed,  everything  indicating  a  long-continued  solfatara  action  within 
the  crater,  which  has  now  entirely  died  away. 

The  upper  portion  of  Lassen’s  Peak  is  an  imperfect  flattened  cone, 
with  an  elliptical  base,  having  its  longer  axis  at  right-angles  to  that 
of  the  Sierra,  so  that,  when  seen  from  the  plain,  it  has  the  appearance 
of  a  very  steep  cone,  while  from  the  mountains  north  or  south  it  looks 
broad  and  dome-shaped.  The  cone  rises  about  2000  feet  above  the 
wide,  gently  sloping  plateau  of  gray  lava  at  its  base.  It  is  principally 
made  up  of  ashes  and  the  debris  of  trachytic  rocks,  from  which  project 
four  precipitous  ridges  of  trachyte,  radiating  from  the  crater  in  various 
directions.  The  highest  point  of  the  crest  is  about  a  hundred  feet 
above  any  other  of  the  remains  of  the  rim  of  the  former  crater,  and 
although  quite  a  sharp  peak,  it  can  be  ascended  to  the  very  summit. 
An  idea  of  the  shape  of  the  upper  portion  of  the  mountain,  as  seen 


GEOL.  VOL.  I. — 40 


314 


GEOLOGY  OF  THE  SIERRA  NEVADA 


from  the  southeast,  may  he  obtained  from  the  annexed  wood-cut  (Fig. 
41),  drawn  from  a  sketch  by  Mr.  King.  The  point  of  view  was  at  a 
distance  of  about  three  miles  from  the  summit,  and  about  2000  feet  of 
vertical  height  is  represented  in  the  figure. 


Fig.  41. 


VIEW  OF  THE  SUMMIT  OF  LASSEN’S  PEAK. 

From  the  volcanic  tables  which  cover  the  region  in  the  vicinity  of 
Lassen’s  Peak,  rise  a  great  number  of  cones  of  all  heights,  several  of 
them  being  nearly  as  elevated  as  the  peak  itself.  Some  of  these  are 
sharp,  pointed  ridges,  while  others  have  well-defined  circular  craters  at 
their  summits.  A  line  of  these  cones  runs  in  a  nearly  northerly  direc¬ 
tion  to  beyond  Pitt  Kiver;  some  of  them  are  nearly  9000  feet  high,  and 
Black  Butte,  about  fifteen  miles  east-northeast  from  Lassen’s,  is  proba¬ 
bly  over  9500  feet  above  the  sea.  Around  the  base  of  this  are  several 
lower  cones,  some  with  finely-formed  craters,  now  covered  with  forests. 

On  the  northeastern  slope  of  the  peak,  at  about  2000  feet  below  the 
summit,  is  a  crater  surrounded  with  vertical  walls,  except  at  one  point; 
the  exterior  slopes  are  covered  with  ashes  and  pumice. 

Four  or  five  miles  north  of  the  summit  of  Lassen’s  Peak,  is  a  cluster 


THE  WESTERN  SLOPE - PLUMAS  COUNTY. 


315 


of  irregular  truncated  cones,  having  all  the  appearance  of  a  very  recent 
origin.  Several  persons  gave  their  independent  testimony  that,  from 
1854  to  1857,  these  cones  were  constantly  emitting  large  quantities  of 
steam  and  gases.  Their  sides  were  found  to  be  of  loose  ashes,  and 
their  broad  summits  were  covered  with  loose  angular  fragments  of 
lava,  as  if  they  had  been  raised  up  and  broken  by  a  force  acting  from 
beneath.  The  rocks  of  which  these  cones  are  made  up  is  that  peculiar 
variety  of  rhyolite  for  which  Richthofen  has  proposed  the  name  of 
“Nevadite.”  It  has  a  resemblance  to  granite,  so  that,  at  a  distance 
and  without  close  examination,  it  would  be  taken  for  that  rock.  The 
minerals  which  make  up  this  curious  variety  of  lava  are  chiefly  quartz 
and  feldspar  (both  sanidin  and  glassy  oligoclase,  according  to  Richt¬ 
hofen),  with  long  slender  prisms  of  hornblende  and  hexagonal  crys- 
tals  of  mica  sparsely  disseminated  through  the  mass.  The  feldspathic 
material  is  drawn  out  into  an  imperfectly  fibrous  form,  which  is  half 
way  between  pumice  and  the  “  Pele’s  hair”  of  the  Sandwich  Island  vol¬ 
canoes.  This  condition  has  evidently  been  the  result  of  the  flowing  of 
the  mass  of  lava  after  the  consolidation  of  the  quartz,  and  while  the 
feldspathic  ingredient  was  still  in  a  plastic  condition.  This  is  shown  by 
the  fact  that  the  threads  or  fibres  are  all  directed  in  one  way,  which 
was  evidently  that  of  the  movement  of  the  mass.  The  quartz  is  pre¬ 
sent  in  very  large  quantity  in  this  rock ;  it  is  transparent,  but  full  of 
fine  flaws  and  cracks. 

The  annexed  wood-cut  (Fig.  42)  will  serve  to  give  an  idea  of  the  out-  • 
line  of  that  part  of  the  volcanic  chain  to  which  Lassen’s  Peak  belongs. 

It  was  carefully  sketched  by  Professor  Brewer,  from  the  cone  ten  miles 
east  of  Fort  Reading,  noticed  on  page  205,  and  from  which  Lassen’s 
Peak  bore  69°  E.  (magnetic).  In  this  diagram  a  is  Crater  Moun¬ 
tain,  b  Lassen’s  Peak,  twelve  miles  south,  while  c  and  d  are  apparently 
the  two  sides  of  an  enormous  crater,  of  which  the  northern  one  (c) 
had  a  distinctly  stratified  appearance,  as  indicated  in  the  figure.  This 
crater  was  very  conspicuous  from  the  peak,  the  rock  appearing  to  be 
black  basalt;  it  was  not  ascended  or  examined  except  from  a  distance. 

S  S  represents  the  snow  line,  in  the  position  it  had  when  the  sketch 
was  made  (October,  1862).  From  d  the  lava  slopes  gradually  down  to 
the  Sacramento  River. 


316 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


On  all  sides  of  Lassen’s  Peak,  evidences  of  the  ex¬ 
istence  of  former  glaciers  were  observed.  The  traces 
of  them  were  most  numerous  and  best  preserved 
at  an  altitude  of  from  7500  to  8000  feet;  but  they 
occurred  in  abundance  between  6000  and  9000  feet. 
An  immense  glacier  formed  on  the  south  slope,  just 
below  the  farthest  cone,  and  flowed  south,  covering 
a  table  several  miles  in  extent  and  descending  to  the 
canons  of  the  Feather  Liver.  Another  one  origi¬ 
nated  along  the  divide  east  of  the  peak,  and  de¬ 
scended  into  the  valley  of  Hat  Creek. 


Section  XII. — The  Xorthern  Counties: — Shasta, 
Tehama,  Siskiyou,  Del  Xorte,  and  Trinity. 

The  geology  of  Lassen’s  Peak  has  been  described 
under  the  head  of  Plumas  County,  as  that  interest¬ 
ing  volcanic  mass  marks  the  corner  of  Plumas, 
Shasta,  and  Siskivou.  Horth  of  this  is  an  immense 
area,  not  less  than  200  miles  long  from  east  to  west, 
and  100  in  the  opposite  direction,  comprised  within 
the  counties  of  Shasta,  Tehama,  Del  Xorte,  Siskiyou, 
and  Trinity.  This  region,  which  is  equal  in  size  to 
the  two  States  of  Vermont  and  Xew  Hampshire, 
has  been  but  little  explored  by  the  Survey,  a  large 
portion  of  it  being  quite  inaccessible  to  a  small 
party,  on  account  of  the  hostile  character  of  the  In¬ 
dians  who  are  sparsely  scattered  over  it.  Some 
parts  of  it  were  examined,  however,  and  the  results 
may  conveniently  be  placed  together  in  one  section. 

The  explorations  in  the  northern  counties  were 
made  during  parts  of  two  different  years.  In  1862, 
the  whole  party  started  from  Shasta  City  and  went 
up  the  Upper  Sacramento  Valley  to  Mount  Shasta, 
making  the  ascent  of  that  great  volcanic  cone,  and 
then  returned  by  the  same  route,  in  order  to  con- 


THE  WESTERN  SLOPE - THE  NORTHERN  COUNTIES.  317 


tinue  the  reconnaissance  down  the  foot-hills  of  the  Sierra  Nevada. 
Previous  to  starting  hack  from  Shasta,  however,  Messrs.  Brewer  and 
Edmond  made  a  hasty  excursion  into  Trinity  County,  as  far  as  Weaver- 
ville.  In  1863,  Messrs.  Brewer  and  King  continued  their  observations 
from  Lassen’s  Peak,  as  noticed  in  the  preceding  section,  north  through 
Shasta  County  by  the  Hat  Creek  road  to  Fort  Crook.  From  this 
point,  they  passed  around  on  the  east  and  north  sides  of  Mount  Shasta 
to  Yreka,  and  thence  to  Crescent  City.  After  examining  the  copper 
mines  in  that  region,  Professor  Brewer  returned  to  San  Francisco  by 
steamer,  and  Mr.  King  by  stage.  The  scattered  observations  made  as 
above  will  be  given  nearly  in  the  same  order  in  which  they  were  taken, 
as  our  information  is  by  no  means  complete  enough  in  regard  to  this 
region,  to  make  it  worth  while  to  endeavor  to  present  it  in  a  systematic 
form. 

For  the  same  reason  we  shall  not  undertake  to  go  into  any  extended 
generalizations  in  regard  to  the  stratigraphical  geology  of  the  northern 
portion  of  the  State ;  but  will  leave  that  for  a  future  volume.  We  may, 
however,  make  a  few  observations,  in  order  to  throw  some  light  on  the 
condition  of  things  in  this  complicated  region. 

As,  in  following  up  the  Sierra,  we  pass  into  Plumas  County  from  the 
south,  we  find  the  grand  simplicity  of  that  chain  to  become  less  and 
less  conspicuous.  This  is  evident  from  the  fact  that  many  persons  con¬ 
sider  the  Sierra  Nevada  to  terminate  in  this  region,  and  do  not  reckon 
Mount  Shasta  as  one  of  the  elevations  which  belong  to  it.  Indeed,  all 
will  admit  that  the  topography  of  the  northern  part  of  the  State  is  not 
easily  to  be  brought  into  harmony  with  that  of  the  Central  Sierra. 
Nor  can  any  entirely  satisfactory  results  be  arrived  at,  in  endeavoring 
to  make  the  connection  between  the  Sierra  and  the  Cascade  Range  in¬ 
telligible,  until  we  know  more  of  the  position  and  age  of  the  great  mass 
of  mountains  which  occupies  the  extreme  northeastern  corner  of  Cali¬ 
fornia. 

We  know,  however,  that  the  vast  overflow  of  volcanic  material, 
which  extends  from  Mount  Shasta  to  Lassen’s  Peak,  lies  upon  the 
same  geological  formations  which  form  the  flanks  of  the  Sierra  farther 
south  through  the  gold-mining  districts.  Wre  know  that  these  appear 
again  to  the  west  and  northwest  of  the  volcanic  formation,  having,  in 


318 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


many  respects,  the  same  lithological  and  metalliferous  character  which 
they  had  to  the  south,  and  being  evidently  a  continuation  of  the  same 
series  of  formations.  We  see  also  that  Mount  Shasta,  itself  an  exclu¬ 
sively  volcanic  mass  like  so  many  of  the  loftiest  summits  of  the  Sierra, 
is  exactly  in  the  line  of  the  axis  of  that  range.  Hence,  for  the  present, 
we  consider  all  the  region  lying  to  the  northeast  of  a  line  drawn  parallel 
with  the  axis  of  the  Sierra  (A.  31°  W.)  from  the  mouth  of  the  Klamath 
River,  as  belonging  to  the  system  of  the  Sierra  Aevada. 

It  is  true,  however,  that  portions  of  this  area  have  been  disturbed 
since  the  deposition  of  the  Cretaceous  series,  and  that  a  part  or  the 
whole  of  the  mountain  ranges  embraced  within  it  owe  a  portion  of 
their  present  elevation  to  changes  which  have  taken  place  while  the 
Coast  Ranges  were  being  uplifted.  The  Cretaceous  strata,  which 
everywhere  along  the  flanks  of  the  Sierra  to  the  south  of  Shasta  City 
are  horizontal  in  position,  to  the  west  and  north  of  that  place  are  up¬ 
turned,  but  not  metamorphosed.  And  as  these  Cretaceous  beds  occupy 
only  very  limited  areas  in  the  region  in  question,  so  far  as  yet  known, 
we  are  unable  to  say  whether  their  disturbance  is  due  to  a  general 
upheaval  or  only  to  a  local  one ;  nor  can  we  yet  trace  the  connection  of 
these  newer  deposits  with  each  other,  or  the  direction  of  the  system  of 
elevations  by  which  they  have  been  disturbed.  A  much  more  thorough 
exploration  of  the  northwestern  corner  of  the  State  will  he  required, 
before  we  can  solve  the  difficult  but  interesting  problems  which  are 
presented  in  this  region,  where  the  systems  of  the  Sierra  and  the  Coast 
Ranges  are  brought  into  direct  contact  with  each  other. 

With  these  few  preliminary  remarks,  we  will  proceed  to  give  the 
results  of  our  reconnaissance  of  the  region  in  question,  commencing 
with  the  vicinity  of  Shasta  City,  and  giving  our  observations  between 
there  and  Weaverville,  in  Trinity  County.  We  will  then  take  up  the 
country  north  and  northeast  of  Shasta  City,  sketching  first  the  geolog¬ 
ical  structure  of  the  Upper  Sacramento  Valley  and  the  vicinity  of 
Mount  Shasta,  ending  the  chapter  with  a  description  of  the  route  of 
our  party  around  from  Lassen’s  Peak  to  Yreka  and  Crescent  City. 
The  order  here  followed  is  almost  entirely  a  geographical  one ;  but  the 
limited  number  of  observations  renders  any  systematic  description  of 
the  country  quite  impossible. 


THE  WESTERN  SLOPE - TIIE  NORTHERN  COUNTIES.  319  • 


The  Sacramento  Valley,  which  was  expanded  into  a  wide  plain  below 
Red  Bluff,  is  contracted  in  width  at  that  point  by  an  elevated  slope  of 
volcanic  materials  which  extends  from  the  base  of  Lassen’s  Peak  on  the 
east  quite  to  the  river,  while  on  the  west  side  there  is  a  heavy  deposit 
of  gravel,  clay,  and  volcanic  tufas,  forming  tables  and  low  bills  from 
the  river  to  the  Coast  Ranges.  At  Red  Bluff  these  deposits  are  at  an 
elevation  of  from  80  to  100  feet,  and  are  deeply  eroded  with  ravines 
separating  rounded  hills ;  these  have  a  dry  soil  and  are  covered  with 
scattered  oaks  and  pines  ( Quercus  Garrycma  and  Pinus  Sabiniana ),  and 
with  a  shrubby  growth  of  Ceanothus  and  Manzanita. 

About  four  miles  north  of  Red  Bluff  a  lower  plain  occurs,  which 
appears  to  have  been  once  the  broad  bed  of  the  Sacramento,  when  it 
flowed  in  a  more  direct  course  and  at  a  higher  level ;  but  the  present 
.  channel  of  the  river  is  in  a  deep  canon,  which  it  has  cut  through  the 
mass  of  materials  forming  the  edge  of  the  great  volcanic  plateau 
coming  down  into  the  valley  from  the  east.  The  surface  of  the  plain  is 
of  indurated  volcanic  tufa,  of  a  light  ash-gray  color,  and  containing 
many  small  fragments  of  pumice.  The  gravel  deposits,  before  alluded 
to,  lie  upon  this  ash  bed  and  contain  numerous  pebbles  of  red  and 
green  jasper,  being  apparently  derived  from  the  metamorphic  Creta¬ 
ceous  rocks  of  the  Coast  Ranges  west.  All  of  these  deposits  lie  nearly 
horizontal.  The  valley  of  Cottonwood  Creek  forms  a  wide  sandy  plain 
at  a  somewhat  lower  level,  and  on  the  north  the  whole  valley  rises  into 
a  table-land  which  expands  out,  in  the  latitude  of  Fort  Reading,  to 
nearly  fifty  miles  in  width,  and  is  from  800  to  1000  feet  high.  It  is 
deeply  eroded  by  the  various  streams  which  flow  down  from  the  moun¬ 
tains  on  both  sides.  This  plateau  is  limited  on  the  north  by  the  moun¬ 
tain  ranges  which  occupy  the  whole  area  beyond  Shasta  City.  These 
do  not  cross  the  State  transversely,  as  represented  on  some  of  the  maps, 
but  have  a  general  northwest  and  southeast  trend,  their  southern  ex¬ 
tremities  terminating  rather  abruptly  at  the  head  of  the  Sacramento 
Valley. 

On  the  north  side  of  the  Cottonwood,  beginning  at  Ilorsetown,  and 
extending  west  to  the  Coast  Ranges,  Cretaceous  strata  lie  at  the  base 
of  the  mountains.  These  strata  were  examined  most  fully  at  Horse- 
town,  Eagle  Creek,  Bee  Creek,  along  the  north  fork  of  the  Cotton- 


320 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


wood,  and  in  tlie  Bald  Hills;  but  there  are  numerous  other  localities 
where  Cretaceous  fossils  are  reported  to  have  been  found. 

From  Horsetown,  eight  miles  southwest  of  Shasta,  to  the  base  of  the 
Coast  Ranges,  the  Cretaceous  strata  form  a  table-land,  about  1200  feet 
high,  and  have  generally  a  southeasterly  dip.  They  have  evidently 
been  denuded  by  the  action  of  the  waves  ^nd  worn  down  to  a  level 
surface,  which  has  since  been  eroded  by  streams  of  water  and  is  now 
intersected  by  numerous  canons  and  gulches.  In  the  localities  exam¬ 
ined  about  the  north  fork  of  the  Cottonwood,  shales  greatly  predomi¬ 
nate,  having  at  least  fifteen  or  twenty  times  the  thickness  of  the  inter- 
stratified  sandstones ;  there  are  also  some  beds  of  conglomerate,  and 
limestone  occurs,  hut  chiefly  in  the  form  of  nodules,  and  very  often 
having  an  Ammonite  as  a  nucleus.  The  strata  in  this  region  have  a 
northeasterly  direction,  and  dip  to  the  southeast  at  an  angle  varying 
from  20°  to  36°,  and  generally  averaging  about  23°.  Some  of  the  beds 
are  highly  fossiliferous  and  have  furnished  many  of  the  largest  and 
finest  Cretaceous  fossils  in  our  collections,  especially  Ammonites,  the 
best  of  these  being  inclosed  in  the  limestone  nodules. 

In  some  of  the  strata  very  large  quantities  of  fossil  wood  are  found, 
and  the  pieces  generally  bear  marks  of  having  floated  long  in  the  water, 
being  worn  on  the  edges  and  partially  decayed ;  they  are  frequently 
bored  by  teredoes,  some  specimens  having  been  perfectly  honeycombed 
by  them  before  sinking  and  becoming  silicified. 

Thin  beds  of  coal  are  not  unfrequent  in  these  shales,  and  near  the 
mouth  of  Iluling  Creek  this  material  has  been  found  in  sufficient  quan¬ 
tities  to  create  some  excitement,  and  to  lead  to  explorations  for  work¬ 
able  beds,  which,  however,  have  not  yet  been  found. 

The  “  Bald  Hills”  are  numerous  rounded  elevations,  lying  between 
the  north  and  middle  forks  of  the  Cottonwood,  and  rising  from  1200 
to  1300  feet  in  height.  They  are  entirely  destitute  of  trees  or  shrubs, 
and  present  a  very  peculiar  appearance.  These  hills  are  mostly  made 
up  of  the  Cretaceous  shales,  and  they  owe  their  remarkable  form  to 
denudation.  With  the  exception  of  the  Bald  Hills,  the  region  is  cov¬ 
ered  with  a  scattered  growth  of  trees,  chiefly  the  Quercus  Garry  ana  and 
Pinus  Sabiniana ,  with  Ceanothus  and  Manzanita.  The  soil  is  partially 
derived  from  the  decomposition  of  the  rock  beneath,  but  there  are 


TIIE  WESTERN  SLOPE - THE  NORTHERN  COUNTIES  321 


many  heavy  beds  of  detrital  materials  which  have  come  from  the  aurif¬ 
erous  slate  formation  in  the  higher  mountains  to  the  northwest,  and  a 
large  portion  of  the  surface  has  been  washed  over  for  gold,  some  of  the 
placers  being  quite  rich.  At  Piety  Hill  this  formation  is,  in  some 
places,  over  100  feet  thick,  and  has  been  found  auriferous  from  the 
bed-rock  to  the  surface. 

The  Cretaceous  strata  of  this  region,  although  not  metamorphosed, 
and  having  generally  a  dip  of  less  than  30°,  have  evidently  been  dis¬ 
turbed  since  their  deposition,  while  the  beds  of  the  same  age  on  the 
other  side  of  the  Sacramento  River,  twenty-five  or  thirty  miles  distant, 
remain  in  their  original  position.  The  local  character  of  this  disturb¬ 
ance  is  made  evident  by  the  varying  direction  and  amount  of  the  dip 
and  the  irregularity  of  the  strike.  The  inclination,  which  is  usually  from 
22°  to  25°,  become.s  in  some  places  as  much  as  36°,  and  the  strike  of 
the  beds,  which  is,  in  the  main,  about  northeast  and  southwest,  varies 
as  much  as  50°,  even  in  short  distances.  On  Alderson’s  Gulch  and 
Bee  Creek,  the  shales  are  found  broken  and  bent,  and  fissures  in  them 
are  seen  to  have  become  filled  up  with  sand,  forming  the  same  kind  of 
dykes  as  were  observed  in  the  Monte  Diablo  Range. 

Between  the  Cretaceous  strata  just  noticed  and  the  high  granitic 
mountains  to  the  northwest,  is  a  large  body  of  the  metamorphic  aurif¬ 
erous  slates.  These  are  scarcely  seen  at  Eagle  Creek;  but  at  Piety 
Hill,  Horsetown,  and  south  of  Shasta,  they  are  well  exposed.  Between 
Shasta  and  Horsetown  they  form  an  elevated  table,  about  1200  feet 
high,  much  intersected  by  ravines,  and  in  many  places  covered  by 
auriferous  detritus.  The  strata  are  quite  contorted,  and  have  a  general 
eastern  dip,  being  usually  very  highly  altered,  although  in  places  they 
are  very  little  changed  from  their  original  character,  and  in  such  cases 
they  resemble  the  rocks  of  the  Cretaceous  series. 

At  Horsetown,  the  unaltered  Cretaceous  shales  are  seen  resting 
directly  on  the  granite,  and  dipping  to  the  east  and  southeast  at  a  low 
angle,  about  15° ;  they  are  of  a  dark-blue  color,  not  in  the  least  meta¬ 
morphic,  and  well  filled  with  fossils.  Very  near  this,  in  fact  not  more 
than  fifty  yards  distant,  the  auriferous  slates  are  seen,  highly  altered 
and  having  a  strike  north  and  south  and  a  high  dip  to  the  east.  It  was 
not  possible,  however,  to  find  any  locality  where  these  metamorphic 


« 


GKOL.  VOL.  T. — 41 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


9  <•)  t ) 


rocks  and  the  unaltered  Cretaceous  could  be  seen  in  contact,  and  some 
difficulty  was  met  with  in  clearly  making  out  whether  the  metamorphic 
beds  might  not  themselves  be  of  Cretaceous  age.  The  weight  of  evi¬ 
dence,  however,  seemed  to  be  decidedly  in  favor  of  the  auriferous  rocks 
being  older  than  the  Cretaceous.  The  older  rocks  seem  to  have  been 
very  irregularly  denuded,  and  a  patch  of  the  underlying  granite  being 
left  bare,  it  was  covered  by  a  deposition  of  sediment  from  the  Cretace¬ 
ous  ocean. 

The  region  about  Shasta  City  is  entirely  of  metamorphic  rocks, 
chiefly  the  auriferous  slates.  On  the  south  of  the  town,  for  six  or  eight 
miles,  these  form  a  plateau  from  1000  to  1100  feet  high,  but  intersected 
by  numerous  and  deep  ravines,  in  which  are  many  placer-mining  claims, 
although  these  are  to  a  large  extent  worked  out.  The  slates  have  a 
general  easterly  dip,  but  are  much  contorted.  Extensive  belts  of  a 
light-colored  rock,  chiefly  made  up  of  quartz  and  feldspar,  occur  on 
both  sides  of  the  town;  this  occasionally  contains  a  little  mica,  and 
becomes  granitic  in  character.  These  belts  run  northeast  and  south¬ 
west,  or  nearly  at  right-angles  to  the  strike  of  the  auriferous  slates. 
From  their  position  and  lithological  character,  they  would  seem  to  be 
large  veins  or  dykes  of  eruptive  origin ;  but  their  real  nature  was  not 
clearly  made  out. 

On  the  southwest  of  Shasta  City,  near  Middletown,  the  metamor¬ 
phic  rocks  rise  in  ridges  over  2000  feet  high,  and  on  the  north  there 
are  still  higher  elevations,  some  probably  exceeding  3000  feet.  Five 
or  six  miles  north  of  the  city,  after  crossing  the  belt  of  quartz  and 
feldspar  rock,  high  ridges  of  metamorphic  slate  are  met  with,  much 
fractured  and  broken  both  in  strike  and  dip.  Hear  the  head  of  Spring 
Creek  large  bodies  of  hematite  iron  ore  occur,  pure  and  of  good  qual¬ 
ity,  ot  which  numerous  boulders  have  been  washed  down  the  canon. 
Under  favorable  circumstances  as  to  fuel  and  labor,  these  deposits 
would  be  very  valuable.  The  quantity  and  quality  of  the  ore  seem  to 
be  all  that  could  be  desired. 

In  passing  northwest  from  Shasta,  on  the  Weaverville  road,  a  ridge 
ot  quartz  and  feldspar  rock  is  crossed  before  passing  Whiskeytown, 
and  this  is  succeeded  by  the  auriferous  slates,  which  occupy  the  surface 
until  the  granite  of  the  Trinity  Mountains  is  reached.  These  slates 


TI1E  WESTERN  SLOPE - THE  NORTHERN  COUNTIES.  323 


are  well  exposed  in  many  places  along  Clear  Creek,  having  a  general 
northwest  and  southeast  direction,  and  dipping  to  the  northeast.  The 
exposures  are  particularly  fine  between  Oak  Bottom  and  Towers’s, 
where  the  slates  are  often  nearly  unaltered,  and  closely  resemble  in  ap¬ 
pearance  the  least  metamorphosed  portion  of  the  auriferous  rocks  in 
the  Central  Sierra. 

The  Trinity  Mountains  extend  along  on  the  west  side  of  Shasta 
County,  stretching  off*  towards  Mount  Shasta,  and  seeming  to  be  the 
northerly  continuation  of  the  main  ridge  of  the  Coast  Ranges,  of  which 
Mount  Linn  and  Mount  St.  John  are  two  of  the  culminating  points. 
Along  the  line  of  Shasta  County,  these  mountains  average  about  4000 
feet  in  elevation;  the  pass  where  the  Weaverville  road  crosses  is  3364 
feet  high,  and  Mount  Bailey,  the  culminating  point,  6357.  The  centre 
of  the  chain  is  of  granite,  which  occupies  a  belt  about  four  miles  wide 
where  the  pass  crosses.  This  rock  is  generally  very  soft  and  decom¬ 
posable,  and  has  bands  of  syenite  in  it  and  patches  of  crystallized  horn¬ 
blende.  Trees  grow  more  abundantly  on  the  decomposing  granite 
than  they  do  on  the  slates,  so  that  the  limits  of  the  two  formations 
may  easily  be  traced,  when  the  country  is  examined  from  a  high  point. 
Mount  Bailey  is  on  a  spur  running  off  to  the  east  from  the  Trinity 
Mountains,  and  Bullet  Chup  is  another  high  point  in  the  main  ridge, 
about  fifteen  miles  west  of  Mount  Bailey.  As  seen  from  the  summit 
of  the  last-named  elevation,  the  granitic  mass  of  Trinity  Mountains 
appears  to  become  much  broader  towards  its  southeastern  end  and  nar¬ 
rows  to  the  northeast,  disappearing  entirely  before  crossing  the  Trinity 
River,  on  the  other  side  of  which  the  same  range  appears  to  be  con¬ 
tinued  in  the  Salmon  Mountains. 

To  the  west  of  this  granitic  belt  the  auriferous  slates  reappear  and 
probably  form  the  predominating  formation  of  Trinity  County. 
Wherever  seen  between  Trinity  Mountains  and  Weaverville,  this  for¬ 
mation  was  found  to  be  much  metamorphosed  and  to  have  a  very  vari¬ 
able  dip  and  strike,  although  usually  inclining  to  the  northeast;  often, 
however,  the  stratification  is  entirely  obliterated.  The  slates  appear 
everywhere  to  be  auriferous.  Near  the  bend  of  Trinity  River  are  very 
rich  placer  and  hydraulic  washings.  From  the  bank  or  plateau  at 
Douglas  City,  over  $1,000,000  is  said  to  have  been  taken  by  the 


324 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


hydraulic  method,  and  a  very  large  amount  of  gravel  still  remains  to 
be  worked. 

A  single  specimen  of  a  fossil,  (Jrioceras  lalus ,  Gabb,  was  found  several 
years  ago  in  a  boulder  in  Trinity  River,  near  the  mouth  of  Reading 
Creek.  It  is  a  very  interesting  ceplialopod,  belonging  to  the  Cretaceous 
series ;  but  its  original  locality  is  a  matter  of  question,  as  it  was  not 
found  in  place,  and  is  the  only  fossil  which  has  yet  been  discovered  in 
the  county.  It  is  to  be  presumed  that  it  may  have  originated  in  the 
mountains  southwest  of  Weaverville,  where  we  may  suppose  the  Cre¬ 
taceous  formation  to  be  largely  developed. 

High  mountains  rise  immediately  north  of  Weaverville,  the  nearest 
considerable  elevation  being  known  as  Mount  Bailey.  “  Bailey”  ap¬ 
pears  to  be  the  Indian  term  for  a  bare  mountain,  and  the  “  Shasta 
Bailey”  is  to  be  distinguished  from  the  “  Trinity  Bailey,”  or  the  one 
near  Weaverville;  the  orthography  of  the  word  is  very  doubtful.  This 
mountain  is  7647  feet  high,  and  another  high  summit  near  the  head  of 
Stewart’s  Fork  was  estimated  at  8250.  These  belong  to  a  range  form¬ 
ing  the  southern  portion  of  the  Salmon  Mountains,  and  have  a  central 
mass  of  granite  of  varying  hardness,  their  crests  weathering  into 
rugged  and  fantastic  pinnacles. 

Trinity  Bailey  is  partly  of  granite,  intersected  by  dykes  of  the  same 
rock,  but  having  a  finer  grain.  On  the  west  side  hornblende-slate 
occurs,  which  is  often  nearly  black,  and  has  veins  of  granite  and  syenite 
running  through  it.  This  region  is  worn  into  deep  and  very  abrupt 
canons,  and  in  these  the  detritus  is  auriferous  wherever  the  slates  have 
been  eroded.  The  flanks  of  this  mountain,  from  a  height  of  4000  to 
7000  feet,  are  covered  with  a  heavy  growth  of  forest  trees,  among  which 
Picea  grandis ,  P.  nobilis ,  Abies  Douglasii ,  Pinus  ponderosa ,  and  P.  Lam- 
bertiana  are  the  predominant  species.  The  Douglas  fir  in  this  region 
often  attains  an  immense  size.  The  direction  of  the  ridge  each  way 
from  the  culminating  point  is  S.  25°  W.  and  N.  33°  E. 

The  region  as  seen  from  the  summit  of  these  two  Baileys  is  exclu¬ 
sively  a  mountainous  one.  Ho  valley  or  plain  of  any  size  is  in  sight, 
and  no  indication  of  a  break,  or  of  a  physical  disconnection  between 
the  Coast  Ranges  and  the  Sierra  Nevada,  can  be  perceived. 

On  the  southwest  of  the  Bald  Hill  region,  at  the  headwaters  of  the 


THE  WESTERN  SLOPE - THE  NORTHERN  COUNTIES.  325 


Cottonwood,  there  are  lofty  mountains,  on  which  snow  remains  all  the 
year,  and  the  highest  peaks  of  which  are  probably  fully  8000  feet  in 
altitude.  The  highest  point  of  this  region  is  known  locally  as  the 
“  Yalloballey,”  an  Indian  name  of  which  the  orthography  and  meaning 
are  doubtful.  It  is  not  unlikely  that  the  Yalloballey  is  the  same  moun¬ 
tain  that  is  indicated  on  the  maps  as  “  Mount  Linn,”  a  name  which,  so 
far  as  we  have  been  able  to  ascertain,  is  not  known  to  any  one  in  this 
part  of  the  State.  The  position  of  this  point  is  uncertain  and  the 
geology  of  the  region  entirely  unexplored,  a  large  part  of  Klamath, 
Trinity,  and  Humboldt  Counties  being  a  very  unsafe  country  to  travel 
in,  owing  to  the  hostile  and  warlike  character  of  the  Indians,  who  have 
almost  unrestrained  possession  of  this  part  of  the  State.  The  natural 
difficulties  in  the  way  of  the  exploration  of  this  region  are  very  great, 
as  the  mountains  are  very  high  and  very  rough ;  besides,  the  heat  of 
the  summer  is  intense,  water  scarce,  and  the  undergrowth  tormenting. 

Of  the  two  roads  from  Shasta  City  to  Yreka,  that  which  crosses  the 
Trinity  Mountains  by  a  skilfully  constructed  grade  is  the  one  travelled 
by  the  stage;  the  other,  which  passes  up  the  valley  of  the  Upper 
Sacramento  River,  is  well  laid  out,  but  not  worked  to  a  sufficient  width 
to  admit  of  passing  with  teams,  except  at  intervals.  It  is  used,  how¬ 
ever,  to  a  considerable  extent,  and  was,  in  1863,  travelled  over  twice  a 
week  by  an  accommodation  stage  from  Red  Bluff  to  Yreka.  Were  the 
beauties  of  this  route  better  known,  there  would  be  a  large  amount  of 
pleasure  travel  over  it  in  the  summer,  for  it  is  hardly  possible  to  find  in 
the  State  a  series  of  grander  views  than  is  presented  by  the  gorge  of 
the  river,  the  rocky  and  forest-clad  sides  of  the  valley,  and  the  stupen¬ 
dous  mass  of  Mount  Shasta  in  the  background,  so  imposing  in  its  out¬ 
line  that  the  most  striking  views  of  it  are  those  which  are  presented  at 
a  distance  of  not  less  than  from  twenty  to  forty  miles.  Every  traveller 
through  the  northern  part  of  California  should  pass  over  the  Sacra¬ 
mento  Valley  road,  by  the  base  of  Mount  Shasta,  either  in  going  or 
returning;  preferably  the  former,  as,  in  that  case,  he  has  the  mountain 
facing  him. 

This  road  crosses  the  Sacramento  River  at  Waugh’s  Ferry,  near 
Shasta  City,  and  runs  northeast  about  fifteen  miles,  to  Bass’s  Ranch. 
Pitt  River  is  crossed  at  Stone’s  Ferry,  a  little  below  the  mouth  of 


326 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


the  McCloud  Fork,  and  from  there  runs  in  a  direction  a  little  west  of 
north  to  the  Sacramento  River,  crossing  it  at  a  point  called  fifteen  miles 
from  Stone’s  Ferry.  At  this  point,  it  unites  with  the  old  trail,  which 
follows  up  the  river  from  Shasta,  most  of  the  way  on  the  west  side,  but 
which  has  not  been  worked  into  a  wagon-road.  The  Upper  Sacra¬ 
mento  is  the  stream  called  “  Destruction  River”  by  the  United  States 
Exploring  Expedition,  and  it  was  down  this  old  trail  that  one  of  their 
parties  travelled,  on  their  way  from  the  Willamet  Valley  to  Sacra¬ 
mento. 

The  rocks  at  Waugh’s  Ferry  are  metamorphie  slates  of  a  bluish-gray 
color;  they  dip  to  the  east  and  southeast,  but  not  at  a  high  angle.  The 
river  at  the  ferry  is  about  125  feet  wide,  and  is  both  deep  and  rapid. 
Between  this  ferry  and  Bass’s  Ranch,  there  are  numerous  gold  wash¬ 
ings  around  the  head  of  Churn  Creek,  at  Buckeye  and  Churntown. 

Near  Bass’s  Ranch  is  a  locality  which  is  very  interesting  to  the  geol¬ 
ogist  as  being  the  only  one  in  the  State  where  any  considerable  number 
of  fossils  have  been  found  in  the  limestone  formation  of  the  Sierra 
Nevada.  The  outcrop  of  this  rock  is  a  very  conspicuous  ridge  or  chain 
of  hills,  extending  in  a  nearly  north  and  south  direction,  and  forming 
several  elevations,  which  are  very  marked  on  account  of  their  peculiar 
grayish-blue  color,  which  is  so  different  from  that  of  the  other  rocks  of 
the  auriferous  series.  These  hills,  which  rise  to  the  height  of  about 
2000  feet  above  the  plain  at  Bass’s,  are  called  on  the  official  map  of 
Shasta  County,  the  Gray  Mountains ;  they  are  also  known  as  the  Mar¬ 
ble  Mountains.  This  limestone  belt  stretches  far  to  the  north,  along 
the  east  side  of  McCloud’s  River,  forming  a  range  known  by  the  same 
name  as  the  river ;  but  its  extension  in  this  direction  was  not  traced 
out  by  us,  for  want  of  time.  Some  of  the  points  in  the  McCloud 
Range  appear  to  be  fully  3000  feet  high  above  the  river. 

The  limestone  formation,  as  seen  in  the  Gray  Mountains,  is  estimated 
at  nearly  1000  feet  in  thickness,  and  it  is  inclosed  in  the  metamorphie 
slates,  with  which  it  is  conformable  both  in  dip  and  strike.  As  farther 
south,  so  here,  this  rock  is  cut  by  heavy  dykes  of  trap,  usually  in  a 
direction  at  right-angles  to  its  strike.  These,  being  here  of  a  more 
easily  decomposable  material  than  the  inclosing  rock,  have  weathered 
so  as  to  leave  large  cavities  or  troughs  in  the  ridges.  The  limestone 


THE  WESTERN  SLOPE - THE  NORTHERN  COUNTIES.  327 


differs  from  that  seen  in  any  other  portion  of  the  State  in  containing 
very  large  masses  of  pyrites  scattered  through  it,  sometimes  of  several 
cubic  feet  in  size.  This  mineral  is  in  radiated  forms,  and  has  under¬ 
gone  a  more  or  less  complete  decomposition,  having  become  converted 
into  brown  oxide  of  iron.  Large  crystalline  masses  of  garnet  also 
occur  in  great  abundance  in  this  rock. 

Fossils  were  first  noticed  in  this  range  by  Dr.  Trask,  who  in  his 
Report  of  1855  mentions  the  locality,  and  correctly  refers  the  formation 
to  the  age  of  the  Carboniferous  group.  A  large  supply  of  material  for 
investigation  was  collected  by  us  at  several  different  localities  along  the 
range,  and  the  whole  was  placed  in  the  hands  of  Mr.  Meek  for  exami¬ 
nation.  His  description  of  these  fossils  will  be  found  in  the  first  sec¬ 
tion  of  the  first  volume  of  the  Palaeontology  of  California,  and  the 
figures  of  the  different  species  are  included  in  plates  1  and  2  of  that 
volume. 

Our  collections  at  this  locality  embraced  about  fourteen  species, 
belonging  to  eleven  different  genera,  viz. :  IAthostrotion ,  Clisiophyllum , 
Chcetetes  or  Alveolites ,  Fusulina ,  Or  this,  Rhynehonella ,  Productus ,  Retzia , 
Spirifer ,  Spiriferina ,  and  Euomphalus.  Of  these  fourteen  species,  six  are 
described  as  new,  and  four  or  five  are  regarded  as  probably  identical 
with  known  forms ;  while  the  remainder  cannot  be  satisfactorily  deter¬ 
mined,  on  account  of  the  imperfect  character  of  the  specimens  collected. 
Mr.  Meek  makes  the  following  remarks  in  regard  to  these  fossils : 

“  Although  generally  in  a  bad  state  of  preservation,  and  imbedded 
in  a  very  hard  limestone  matrix,  they  retain  enough  of  their  original 
characters  to  establish,  beyond  a  doubt,  their  Carboniferous  age.  They 
are  scarcely,  however,  sufficient,  in  the  present  state  of  our  knowledge, 
to  warrant  a  positive  opinion  in  regard  to  their  exact  stratigraphical 
position  in  the  Carboniferous  system,  though  I  am  much  inclined  to 
think  that  they  belong  below  the  horizon  of  the  Coal  Measures.  The 
strongest  evidence,  to  my  mind,  in  favor  of  this  conclusion,  is  the 
presence  among  them  of  a  coral  which  I  cannot  distinguish  from  JAtho- 
strotion  mamillare ,  a  common  and  widely-distributed  species  in  the  Sub- 
carboniferous  rocks  of  the  Mississippi  Valley.  So  far  as  my  knowledge 
extends,  this  coral  has  never  been  found  in  the  Coal  Measures,  nor  far 


328 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


above  the  position  of  the  St.  Louis  limestone  of  the  Western  Subcar- 
boniferous  series. 

“  To  a  European  geologist,  unacquainted  with  the  range  of  the  vari¬ 
ous  types  of  fossils  in  our  Carboniferous  rocks,  the  occurrence,  in  this 
collection,  of  species  either  identical  with,  or  closely  allied  to,  such 
forms  as  Fusulina  cylindrical  Spirifer  lineatus ,  and  Productus  semireticu- 
latus ,  would  also  be  regarded  as  additional  evidence  of  the  Subcarbon- 
ife rous  age  of  the  rock  in  which  they  occur.  I  do  not,  however,  allow 
so  much  weight  to  the  presence  of  these  fossils,  because  we  find,  often 
in  considerable  abundance  and  widely  distributed  in  our  Coal  Measures, 
forms  that  have  been  pronounced  identical  with  these,  even  after  a 
direct  comparison  of  American  and  foreign  specimens,  by  European 
palaeontologists.  It  is  also  well-known  to  those  familiar  with  the  Car¬ 
boniferous  Fauna  of  the  Mississippi  Valley,  that  great  numbers  of  brach- 
iopods,  gasteropods,  corals,  and  other  marine  remains  occur  in  our 
Western  Coal  Measures  often  closely  allied  to  forms  rarely,  if  ever, 
found  above  the  horizon  of  the  Subcarboniferous  rocks  in  Europe.  So 
strikingly  is  this  fact  exemplified,  that  we  should  be  almost  tempted  to 
adopt  the  conclusion  that  the  Coal  Measures  of  the  West  rather  repre¬ 
sent  some  upper  member  of  the  Subcarboniferous  series  of  the  Old 
World,  than  the  Coal  Measures  proper,  as  developed  there,  were  it  not 
for  the  fact  that  the  Flora  of  these  strata  is  known  to  be  remarkably 

I 

like  that  of  the  European  Coal  Measures ;  so  much  so,  indeed,  that 
competent  authorities  pronounce  a  very  large  proportion  of  the  species 
in  all  respects  identical.  The  testimony  of  these  plants  is  also  corrob¬ 
orated  by  the  physical  structure  of  our  entire  Carboniferous  system,  as 
developed  in  the  States  lying  within  the  Valley  of  the  Mississippi. ” 

The  limestone  belt  of  the  Sierra  has  been  proved  to  be  of  Carbonif¬ 
erous  age  at  Bass’s  Ranch,  and  also  at  Pence’s,  about  eighty  miles 
southeast  of  Bass’s.  The  same  rock  in  Genesee  Valley  contained  traces 
of  fossils,  which  were  considered  by  Mr.  Gabb  as  probably  belonging 
to  the  same  epoch.  In  no  other  of  the  numerous  outcrops  of  crystal¬ 
line  limestone  in  the  Sierra  have  any  recognizable  fossils  been  obtained; 
but,  from  their  general  lithological  resemblance  to  each  other,  and  their 
position  in  relation  to  the  auriferous  slate  series,  it  is  thought  probable 
that  all  these  are  of  one  and  the  same  as;e.  It  is  almost  certain  that 

o 


THE  WESTERN  SLOPE - THE  NORTHERN  COUNTIES.  329 


the  different  masses  which  make  up  the  most  western  of  the  belts  of 
limestone  which  can  be  traced  through  the  Sierra  are  all  Carbonifer¬ 
ous;  but  whether  the  other  outcrops,  which  occur  much  higher  up  in 
the  mountains,  and  which  appear  to  form  one  or  more  distinct  belts, 
are  of  the  same  a°’e  remains  to  be  demonstrated.  Our  researches  in 

O 

the  Sierra  Nevada  have  not  yet  been  sufficiently  extensive  to  justify  an 
attempt  to  settle  this  question  on  purely  stratigraphical  evidence. 

Near  Stone’s  Ferry,  on  the  north  side  of  Pitt  River,  there  is  a  high 
ridge  of  granitic  rock,  in  places  resembling  the  quartz  and  feldspar 
rock  of  the  vicinity  of  Shasta  City  ;  but  its  extent  to  the  north  was  not 
traced  out.  It  is  probably  an  isolated  mass  included  in  the  auriferous 
series.  Crossing  this,  we  come  upon  the  regular  slate  formation,  which 
occupies  most  of  the  region  along  the  road,  between  McCloud’s  Fork 
and  the  Upper  Sacramento.  Near  to  the  granite,  and  for  some  dis¬ 
tance  farther  north,  the  slates  are  a  good  deal  altered  and  broken  up 
by  intrusions  of  trappean  rock  and  granite.  Beyond  this  we  meet  with 
slates  which  are  very  little  metamorphosed,  and  which  have  every¬ 
where  an  eastern  or  northeastern  dip,  at  an  angle  varying  from  20°  to 
50°.  The  country  is  a  wilderness  of  high  rolling  hills,  rather  dry,  and 
covered  with  scattered  oaks  and  pines,  and  with  an  undergrowth  of 
oak  chaparral. 

At  the  crossing  of  the  Sacramento,  the  rocks  are  hard  metamorphic 
slates,  which  soon  pass  into  almost  entirely  unaltered  shales ;  indeed, 
hardly  any  portion  of  the  Sierra  Nevada  shows  so  large  an  extent  of 
sedimentary  rock,  in  a  condition  so  nearly  approaching  that  in  which 
it  was  originally  when  deposited,  as  this  along  the  western  side  of  the 
Upper  Sacramento.  The  dip  of  these  rocks  is  everywhere  to  the  east, 
and  usually  at  an  angle  of  about  30°  ;  their  strike  becomes  more  nearly 
north  and  south  as  we  go  northward.  The  rocks  come  close  down  to 
the  river,  forming  steep  slopes,  along  the  sides  of  which  the  road  is 
notched  out,  being  often,  for  long  distances,  not  wide  enough  for  two 


wagons  to  pass.  These  hills  rise  in  places  to  3000  feet  above  the  river. 
In  these  unaltered  |>ocks  careful  search  was  made  for  fossils,  at  many 
points,  but  without  success.  At  a  locality  a  mile  and  a  hall  south  ol 
Bog  Creek,  the  strike  of  the  slates  is  about  N.  20°  E.,  and  their  dip 
from  45°  to  50°  to  the  east.  At  Slate  Creek  also,  the  schistose  rocks 


GEOL.  VOL.  I. — 42 


330 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


are  beautifully  exposed,  and  they  pass  into  a  kind  of  flagstones;  the 
dip  continuing  to  be  in  an  easterly  direction. 

From  Portuguese  Flat,  a  little  above  Slate  Creek,  going  north,  the 
slates  are  more  metamorphic  and  begin  to  contain  quartz  veins.  In 
this  region  there  has  been  considerable  prospecting  for  placer  and 
quartz-mines,  and  there  are  gold  washings  in  the  bed  of  the  river, 
which  are  said  to  pay  well.  Between  Slate  and  Castle  Creeks  there  is 
a  large  amount  of  coarsely  crystallized  hornblende-rock,  with  many 
trappean  and  metamorphic  varieties,  the  formation  growing  more  and 
more  crystalline  as  we  approach  the  granitic  range  of  which  Castle 
Rock  forms  the  termination  on  the  river. 

These  metamorphic  rocks  are  almost  everywhere  covered  by  a  heavy 
mass  of  volcanic  materials,  which  first  begin  to  be  seen  three  miles 
after  crossing  the  Sacramento ;  and,  as  we  go  north,  we  find  this  for¬ 
mation  occupying  more  and  more  of  the  surface.  As  the  road  rises  in 
elevation,  following  up  the  river,  which  has  a  very  rapid  fall,  the  lava 
appears  lower  and  lower  down ;  until  finally,  before  reaching  Castle 
Rock,  the  slates  are  seen  only  in  the  gulches  near  the  water.  Beyond 
this  granitic  range,  they  sink  altogether  out  of  sight,  and  the  road 
keeps  entirely  on  the  volcanic  formation. 

Between  Sweetbrier  Ranch  and  Castle  Rock,  all  the  streams  contain 
boulders  of  granite,  syenite,  and  hornblende-rock.  In  crossing  one  of 
the  spurs  of  the  Castle  Range,  two  and  a  half  miles  from  Sweetbrier, 
large  veins  of  granite  were  observed  in  the  highly  altered  and  much 
contorted  slates  ;  over  these  the  lava  occurs  in  places  and,  in  close  prox¬ 
imity,  the  granite  rises  through  the  whole,  it  being  apparent,  from  the 
position  of  the  different  formations,  that  the  granite  has  been  forced  up 
from  below  through  the  slates,  in  consequence  of  which,  or  after  which, 
an  extensive  metamorphism  of  the  latter  took  place,  followed  by  long- 
continued  denudation,  leaving  an  irregular  surface,  over  which  the 
lava  streams  flowed,  probably  from  Mount  Shasta  or  some  of  the 
smaller  cones  adjacent  to  it.  No  changes  have  occurred  since,  except 
the  continued  denudation  and  erosion  of  the  surface,  of  which  the 
eruptive  materials,  as  well  as  the  underlying  slates,  show  abundant 
evidence. 

The  Castle  Range,  which  terminates  on  the  river  in  a  conspicuous 


THE  WESTERN  SLOPE - THE  NORTHERN  COUNTIES.  331 


peak  called  Castle  Rock,  is  a  spur  of  the  Trinity  Mountains,  running 
nearly  east  from  the  main  range.  It  is  a  ridge  of  granite,  rising  about 
2500  feet  above  the  valley,  and  having  an  extremely  sharp  and  serrated 
outline.  The  upper  part  of  the  mountain  is  a  ragged  crest  of  pinnacles 
and  spires  of  a  light-gray  color,  presenting  a  most  imposing  appearance 
from  the  south  side,  as  is  faintly  indicated  in  the  annexed  wood-cut 
(Fig.  43)-.  In  the  valley  on  the  north  side  of  this  range,  beautiful 


Fig.  43. 


CASTLE  ROCK  RANG  E. 


specimens  of  rose-colored  feldspar  were  collected,  in  large  crystals. 
Hypersthene-rock  and  a  variety  of  coarsely-crystallized  hornblende- 
rock  occur  also  in  the  ravines  on  this  side  of  the  granite.  The  por¬ 
tion  of  the  Trinity  Mountains  with  which  Castle  Range  connects 
appears  to  be  entirely  unexplored ;  it  is  a  wild  and  forbidding  region. 

There  are  two  groups  of  mineral  springs  in  this  vicinity,  one  ot 
which  is  on  the  east  side  of  the  Sacramento,  nearly  opposite  the  mouth 
of  Castle  Creek;  the  other  is  three  and  a  half  miles  farther  up  and 
eight  miles  from  Strawberry  Flat,  at  the  base  of  Mount  Shasta.  The 
first  is  called  u  Lower  Soda,”  the  other  “  Soda  Springs.  ’  I  he  latter 


332 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


are  in  the  canon  of  the  Sacramento,  at  an  elevation  of  2363  feet,  and 
they  are  considerably  resorted  to,  the  water  having  a  high  reputation 
for  its  tonic  effect,  and  being  reported  to  have  a  specific  action  on  the 
kidneys.  The  water  is  a  chalybeate,  there  being  an  extensive  ferrugi¬ 
nous  deposit  around  the  spring ;  it  is  also  highly  impregnated  with 
carbonic  acid,  sparkling  like  soda-water,  whence  the  name,  which  is 
one  usually  given  in  California  to  springs  giving  off  carbonic  acid,  and 
not  to  those  containing  carbonate  of  soda.  The  temperature  of  the 
water  was  52°,  in  September,  1862. 

From  Soda  Springs  to  Strawberry  Flat,  a  distance  of  eight  miles, 
lava  covers  the  surface,  forming  a  gradual  slope,  heavily  covered  with 
a  magnificent  forest  vegetation,  chiefly  of  pines  and  firs.  From  a  hill 
a  little  to  the  east  of  the  road,  about  two  miles  south  of  the  Lower 
Soda  Springs,  one  of  the  finest  possible  views  of  Mount  Shasta  may  be 
obtained,  the  distance  being  just  about  sufficient  to  give  full  effect  to 
the  mountain  mass,  and  the  ragged  cliffs  in  front  furnishing  such  a 
foreground  as  any  artist  with  a  feeling  for  rocks  would  delight  in  paint¬ 
ing;  these,  and  the  noble  forests  by  which  they  are  crowned,  form  a 
worthy  frame  for  the  stupendous  snowy  mass  in  the  background. 

Mount  Shasta  has  always  been  ascended  from  the  west  side,  Straw¬ 
berry  Flat  being  the  most  convenient  and  suitable  point  for  making 
the  necessary  preparations  for  the  trip.  The  route  followed  to  the 
summit  of  the  mountain  is  an  easy  and  natural  one,  and  it  is  hardly 
possible  that  any  other  can  be  found  which  will  be  as  desirable;  indeed, 
so  far  as  our  observations  go,  we  are  unable  to  say  where  any  other 
practicable  one  could  be  laid  out. 

The  mountain  lias  been  ascended  quite  a  number  of  times;  in  fact, 
hardly  a  summer  passes,  that  one  or  more  parties  from  Yreka  does  not 
reach,  or  attempt  to  reach,  the  summit.  To  one  possessed  of  sound 
lungs  and  accustomed  to  mountain-travelling,  there  is  no  difficulty  in 
the  ascent,  except  such  as  arises  from  the  system  having  to  adapt  itself 
so  suddenly  to  the  rarefied  condition  of  the  air  at  an  elevation  of  over 
14,000  feet. 

There  is  no  regular  guide  to  conduct  parties  up  the  mountain;  but 
Mr.  J.  H.  Bisson,  the  attentive  landlord  of  the  hotel  at  Strawberry 
Flat,  has  accompanied  travellers  to  the  summit,  and  will  undoubtedly 


THE  WESTERN  SLOPE - THE  NORTHERN  COUNTIES.  333 


aid  and  advise  all  who  desire  to  make  the  ascent.  The  time  will 
undoubtedly  come,  when  the  travel  to  this  beautiful  spot  will  be  suffi¬ 
cient  to  justify  more  ample  preparations  than  have  yet  been  made  to 
accommodate  those  who  seek  to  climb  Mount  Shasta.  It  is  hardly 
possible  to  exaggerate  the  beauty  and  grandeur  of  the  views  from  this 
point,  so  that  those  who  do  not  feel  equal  to  the  task  of  ascending  to 
the  summit  will  find  themselves  amply  repaid  for  visiting  Strawberry 
Flat,  by  the  nearer  view  of  the  mountain  itself  from  that  place,  as  well 
as  the  clear  water,  cool  air,  and  magnificent  forest  vegetation,  which 
are  so  grateful  to  the  traveller  who  comes,  during  the  summer  months, 
from  the  burning  plains  of  the  Sacramento  Valley,  or  the  alkaline  de¬ 
serts  of  Nevada. 

The  best  season  of  the  year  for  the  ascent  of  Mount  Shasta  is  in  the 
months  of  July  and  August.  Before  July  the  snow  is  hardly  gone 
from  the  camping-ground,  from  which  the  ascent  to  the  summit  and 
the  return  is  to  be  made  in  one  day ;  and,  after  that  month,  the  inces¬ 
sant  fires  in  the  surrounding  forests  fill  the  air  with  smoke  and  take 
away  all  distinctness  from  the  distant  view.  The  plan  adopted  by  those 
ascending  the  mountain  is,  to  pass  the  first  night  at  Camp  Ross,  near 
the  line  of  perpetual  snow,  and  from  that  point  to  start  the  next  morn¬ 
ing  sufficiently  early  to  keep  always  on  the  hard  frozen  snow,  the  heat 
of  the  sun  by  mid-day  softening  it  nearly  to  the  summit,  so  as  to 
make  climbing  almost  if  not  quite  impossible,  while  the  ascent  on  the 
frozen  surface  is  very  easy,  especially  if  one  has  the  soles  of  his  boots 
well  provided  with  nails.  Our  party  started  at  3J  a.m.,  and  reached 
the  summit  at  11J ;  but  others  not  encumbered,  as  we  were,  by  barom¬ 
eters  and  instruments  of  various  kinds,  would  be  able  to  make  the 
ascent  in  considerably  less  time,  if  in  other  respects  on  an  equality  with 
us  as  regards  their  climbing  powers.  Of  course,  a  night  near  the  full 
of  the  moon  is  preferable  for  this  expedition,  although  the  usual  bright 
starlight  of  the  summer  in  this  region  will  answer,  to  enable  one  to 
pick  his  way  over  the  snow. 

It  is  advisable  to  leave  Strawberry  Flat  in  season  to  camp  early  and 
comfortably  at  the  base  of  the  snow,  and  to  have  plenty  of  warm  cloth¬ 
ing,  as  the  temperature,  at  an  altitude  of  7629  feet,  will  probably  be 
pretty  near  the  freezing-point  before  morning.  There  is  an  abundance 


334 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


of  wood  and  water  at  Camp  Ross,  as  the  station  half  way  np  the  moun¬ 
tain  is  called,  and  the  trail  from  Strawberry  is  sufficiently  good  to  allow 
those  wishing  to  save  their  strength  to  ride  nearly  the  whole  way. 
The  trail  passes  through  one  continuous  forest  of  magnificent  conifer¬ 
ous  trees.  In  the  lower  regions  the  sugar  and  pitch  pines  predominate  ; 
but  cedars  and  firs  gradually  take  their  place,  the  former  becoming  less 
abundant  as  we  rise.  As  the  forest  vegetation  of  Mount  Shasta  adds 
much  to  the  grandeur  and  beauty  of  the  scenery,  and  as  this  is  a  con¬ 
venient  opportunity,  we  introduce  a  few  remarks  on  the  subject  of  the 
distribution  of  the  trees  in  this  region,  which  are  chiefly  drawn  from 
the  notes  of  Professor  Brewer. 

The  base  of  Mount  Shasta  is  clothed  with  forests  everywhere  except 
on  its  north  side.  In  this  direction  a  valley  stretches  northward  to  the 
Klamath  River,  and  the  side  of  the  mountain  which  leads  down  to  it  is 
covered  with  too  scanty  a  soil  to  support  any  more  vigorous  growth 
than  that  of  scattered  cedars  and  oaks,  which  seldom  rise  to  over 
thirty  feet  in  height ;  there  is,  however,  a  pretty  dense  undergrowth, 
among  which  the  manzanita  is  the  predominating  shrub.  The  valley 
itself,  into  which  the  north  slope  of  the  mountain  descends,  is  quite 
destitute  of  trees,  and  lies  at  an  elevation  of  from  2500  to  3000  feet 
above  the  sea.  This  valley  is  not  a  level  plain,  but  has  a  great  number 
of  gently  rolling  hills  scattered  over  it.  These  are  a  few  hundred  feet 
high,  and  are  also  treeless,  but  covered  for  the  most  part  with  a  low 
herbaceous  vegetation,  which  ripens  and  dries  up  in  the  early  summer. 
Limited  areas  have  a  thick  growth  of  chaparral  over  them,  consisting  of 
manzanita,  sage,  chamiso,  and  greasewood. 

The  finest  forests  are  found  on  the  southern  and  western  slopes  of 
the  mountain,  and  the  route  usually  taken  to  the  summit  affords  as 
good  an  exhibition  of  all  the  varieties  of  trees  and  their  distribution  at 
different  altitudes  as  could  be  desired.  At  Strawberry  Flat,  at  an  ele¬ 
vation  of  about  3600  feet,  the  forests  are  of  the  character  observed 
everywhere  in  the  northern  part  of  the  State  at  that  height.  The  larg¬ 
est  trees  are  the  pitch  pines  (Pinus  ponderosa),  which  not  uncommonly 


attain  a  diameter  of  ten  or  twelve  feet  and  an  elevation  of  two  hundred 
and  fifty.  This  is  a  stately  tree,  symmetrical  in  outline,  as  well  as 
gigantic  in  size.  Its  most  striking  feature,  next  to  its  height,  is  the 


TI1E  WESTERN  SLOPE - THE  NORTHERN  COUNTIES.  335 


size  of  the  plates  of  the  bark.  These  are  smooth,  of  a  bright  cinna¬ 
mon  color,  and  often  as  much  as  twenty  inches  wide  and  three  feet 
long.  The  crevices  between  these  plates  are  often  blackened  by  tire, 
making  their  smooth  surface  and  bright  color  more  conspicuous. 

At  this  altitude  and  lower,  down  to  the  Sacramento  River,  the  forests 
are  chiefly  made  up  of  the  following  species :  sugar  pine  ( P.  Jximber- 
tiana .),  spruce  ( Abies  Douglasii ),  bastard  cedar  (Librocedrus  decurrens ), 
Oregon  cedar  ( Ciipressus  Jxucsoniana—C.  fragrcms  of  Kellogg),  black 
oak  ( Q.  Sonomensis ),  live  oak  ( Q.  crassipocula ),  and,  along  the  streams, 
an  occasional  yew  ( Taxus  brevifolia).  The  undergrowth  is  formed  of  a 
variety  of  shrubs,  among  which  several  species  of  Ceanothus  are  abun¬ 
dant.  The  California  chinquapin  ( Castanopsis  chrysopliylla )  covers  large 
areas,  occurring  in  dense  masses.  This  species  grows,  in  Oregon,  to 
the  size  of  a  tree,  but  here  is  a  bush  not  often  more  than  six  feet  high, 
and  occasionally  forming  a  dense  chaparral.  It  is  an  evergreen,  and 
the  dark  glossy  upper  surface  of  its  leaves  contrasts  beautifully  with 
the  bright  golden-yellow  of  the  lower.  The  flower,  which  resembles 
that  of  the  chestnut,  remains  on  the  stem  for  some  months  and  adds 
to  the  picturesque  effect  of  the  .species.  A  cornus  ( C .  Nuttalii )  is  com¬ 
mon  in  this  region,  and  is  a  small  tree  with  very  conspicuous  flowers, 
reminding  one  of  the  dogwood  of  the  Eastern  forests.  A  species  of 
maple  ( Acer  macrophyllum )  grows  to  the  size  of  a  tree  along  the  streams, 
but  is  not  abundant;  another  species  ( A .  circinatum)  is  common,  form¬ 
ing  in  places  a  tangled  undergrowth.  Manzanita  is  not  rare,  and  other 
shrubs  occur.  Herbaceous  plants  are  numerous,  and  some  hundreds 
of  species  might  be  collected  by  the  botanist  in  this  vicinity. 

The  above-mentioned  trees  and  shrubs  form  together  the  vegetation 
of  the  valleys  and  lower  elevations  around  the  base  of  Mount  Shasta. 
Some  of  the  species  descend  to  the  level  of  the  sea,  while  others 
extend  up  into  much  higher  altitudes. 

The  great  forest  belt  of  the  mountain,  however,  lies  higher,  at  an 
elevation  of  from  4000  to  7000  feet  above  the  sea.  Of  this  belt  all  the 
most  conspicuous  trees  belong  to  the  family  of  the  Coniferce ,  and  the 
forests  of  this  region,  as  well  as  their  continuation  along  the  coast  far¬ 
ther  north,  are  unsurpassed,  and  probably  unequalled,  in  grandeur,  by 
those  of  any  other  part  of  the  world.  Ten  or  twelve  species  occur,  but 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


the  principal  effect  is  produced  by  eight  of  them,  all  of  which  attain  at 
times  a  diameter  of  over  six  feet,  and  a  height  of  over  200,  while  sev¬ 
eral  are  often  over  250,  and  some  as  much  as  800  feet  high.  These 
species  are  : 


Sugar  Pine, 
Pitch  Pine,  . 

Li  U 

Bastard  Cedar,  . 
Douglas  Spruce, 
Fir, 

i  i 

k  L 


Pinus  Lambertiana. 

P.  pojulerosa. 

P.  Jeffreyi. 

Librocedrus  decurrens. 
Abies  Douglcisii. 

Picea  grandis. 

P.  amabilis. 

P.  nobilis. 


Pinus  contorta ,  P.  Balfouriana ,  P.  tuberculata ,  and  two  or  three  species 
of  fir  and  spruce,  besides  those  named  above,  also  occur ;  but  are  not 
among  the  common  and  conspicuous  trees. 

Of  these  species  the  sugar  pine  is  the  grandest  tree.  It  occurs  at 
all  altitudes  between  3000  and  6000  feet ;  but  attains  its  greatest  dimen¬ 
sions  between  4000  and  5000  feet,  where  it  is  frequently  300  feet  high. 
Its  trunk  is  perfectly  straight,  its  head  symmetrical,  and  from  the 
slightly  drooping  ends  of  the  horizontal  branches,  the  enormous 
cones  hang  down  in  bunches  of  two  or  three,  like  tassels.  One  tree, 
measured  by  us,  was  found  to  be  300  feet  high,  without  a  flaw  or 
curve  in  its  trunk,  and  only  seven  feet  in  diameter  at  the  base. 
These  forests  are  rather  open,  the  trees  being  seldom  densely  aggre¬ 
gated  ;  and,  owing  to  the  dryness  of  the  air*  their  trunks  are  very  free 
from  mosses  and  lichens. 

As  we  go  higher  on  the  sides  of  the  mountain*  among  the  forests,  we 
find  the  pines  decreasing  in  number,  wliile  firs  are  constantly  becoming 
more  abundant.  Picea  nobilis  is  the  predominating  species  at  7000  to 
7500  feet.  All  the  species  of  firs  which  are  found  here  are  very  beau¬ 
tiful.  They  all  attain  a  large  size,  are  very  symmetrical  in  their  growth, 
and  have  a  very  dark-green  and  brilliant  foliage,  which  is  very  fragrant. 
The  branches  are  often  very  regularly  and  pinnately  divided,  producing 
a  most  brilliant  effect.  The  color  of  the  sky  is  perceptibly  darker,  as 
seen  through  this  peculiar  foliage  raised  in  a  canopy  so  high  above  the 
observer.  Taken  together,  the  grandeur  of  the  forests,  the  clear  and 


THK  WESTERN  SLOPE 


THE  NORTHERN  COUNTIES.  337 


deep  blue  of  the  sky,  and,  towering  in  the  background,  the  mighty 
snow-covered  mass  of  Mount  Shasta  itself— these  all  form  a  picture  of 
the  effect  of  which  no  language  can  convey  an  idea. 

Here  and  there,  the  forests  are  interrupted  by  large  patches  of  cha¬ 
parral,  locally  known  as  “  Devils’  Acres.”  These  are  sometimes  of  a 
square  mile  or  more  in  area,  and,  as  seen  from  a  distance,  look  as 
smooth  and  green  as  the  most  carefully  kept  lawn ;  but  the  unhappy 
mortal  who  should  attempt  to  penetrate  one  of  them,  would  soon  make 
a  personal  experience  of  the  propriety  of  the  name,  in  both  its  parts. 
These  patches  of  chaparral  are  made  up  of  a  single  species  of  Cecm- 
othus  ( C.  velutinus  f)  which  forms  the  densest  possible  undergrowth, 
and  also  occurs  scattered  through  the  forests.  Generally,  however, 
the  woods  are  quite  open,  the  undergrowth  being  only  sparsely  distri¬ 
buted  over  the  surface. 

The  forests  cease  very  suddenly  at  the  elevation  of  about  8000  feet, 
the  trees  maintaining  their  usual  dimensions  nearly  up  to  this  altitude, 
and  then  disappearing  at  once.  A  Picea  nobilis  was  measured  near 
Camp  Ross,  at  a  height  of  7600  feet,  which  was  six  feet  in  diameter, 
although  the  snow  lay  quite  near  in  the  forests  and  ravines,  at  this 
season,  September,  1862,  when  its  quantity  was  at  a  minimum.  About 
500  feet  higher,  the  trees  were  found  to  have  ceased  altogether. 

Above  this  limit  of  the  tree-vegetation  on  Mount  Shasta,  a  few  spe¬ 
cies  still  exist  as  shrubs,  and  struggle  for  an  existence  up  to  a  height  of 
about  9000  feet,  or  possibly  a  little  more  in  some  sheltered  nooks.  Of 
these,  a  pine  (P.  albicaulis ,  or  P.  flexilis,  of  the  English  botanists)  is  the 
most  important.  This  species  grows,  as  a  shrub,  in  favorable  places, 
up  to  9000  feet,  and  small  trees  were  seen  so  compacted  by  the  pres¬ 
sure  of  the  snow  on  them  in  the  winter,  that  a  man  could  easily  walk 
over  the  flat  surface  formed  by  their  foliage.  The  upper  part  of  the 
mountain  is  extraordinarily  bare  of  vegetation,  neither  shrub,  nor 
flower,  nor  even  moss  or  lichen  occurring  anywhere  within  a  range  of 
3000  to  4000  feet  below  the  summit.  This  is  perhaps  the  most  marked 
difference  which  the  botany  of  this  mountain  shows,  as  compared  with 
that  of  the  Alps,  or  other  lofty  chains  in  Europe.  The  long,  rainless 
summer  of  California  is  peculiarly  unfavorable  to  the  development  of 
a  rich  herbaceous  vegetation  ;  only  the  forest  trees,  with  their  deep- 


OEOL.  VOL.  I. — 43 


338 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


reaching  roots,  can  live  through  it.  Here,  on  Mount  Shasta,  we  see 
true  forests  extending  up  to  where  the  snow  lies,  in  sheltered  patches, 
through  the  whole  of  an  ordinary  summer;  while  trees  attain  a  large 
size  in  a  climate  which,  taking  temperature  alone  into  consideration, 
would  only  produce  shrubs  in  Europe.  Several  species  of  trees  on  this 
mountain,  as  well  as  elsewhere  in  the  Sierra  Nevada,  attain  a  diameter 
of  four  feet  in  localities  where  it  freezes  during  nearly  every  night  in 
the  year.  The  upland  pastures,  which,  in  Europe,  intervene  between 
the  forests  and  the  snow,  have  no  representation  in  California,  nor  are 
any  of  the  Alpine  species  sufficiently  abundant  here  to  form  a  notice¬ 
able  element  in  the  scenery.  So  far  as  our*  botanical  collections  have 
been  examined,  the  Flora  of  these  upper  regions  is  found  to  be  much 
more  nearly  allied  to  that  of  the  Arctic  zone  than  of  the  Alps. 

The  only  signs  of  life  on  the  upper  part  of  the  mountain  was  the 
“red  snow,”  which  was  seen  over  a  very  considerable  area,  and  chiefly 
at  an  elevation  of  from  8000  to  12,000  feet.  In  our  descent,  when  the 
snow  was  softened  by  the  warmth  of  the  sun,  our  footprints  were  of  a 
blood-red  color,  owing  to  that  low  form  of  vegetable  life,  called  “ Pro¬ 
tococcus  nivalis ,”  and  which  is  so  characteristic  of  the  high  Alpine 
regions  in  other  parts  of  the  world. 

It  was  a  bright  moonlight  night  when  our  party  made  the  ascent, 
the  moon  being  about  three  days  past  the  full,  and  we  were  able  to 
pick  our  way  over  the  snow  without  any  difficulty ;  it  was  quite  hard 
and  rough,  so  that  we  did  not  slip  on  it  much,  especially  as  our  boots 
were  well  provided  with  nails,  which  are  decidedly  better  than  “creep¬ 
ers.”  Those  who  had  barometers  to  carry,  of  which  two  were  taken 
up,  found  a  sort  of  long  walking-stick,  or  roughly  improvised  “  Alpen- 
stocke,”  almost  indispensable.  We  also  took  with  us  a  small  supply  of 
eatables,  and,  what  was  more  important,  a  large  canteen  of  water,  as 
the  quenching  of  thirst  by  melting  snow  in  the  mouth  is  highly  inju¬ 
rious.  It  may  here  be  added,  as  a  hint  to  mountain  climbers,  that  the 
use  of  either  wine  or  alcoholic  beverages  of  any  kind,  when  hard  work 
is  to  be  done,  is  not  to  be  recommended,  if  our  experience  can  be 
trusted.  We  wore  thick  clothing,  and  found  it  necessary  at  the  sum¬ 
mit,  and  not  at  all  inconvenient  in  going  up. 

The  first  part  of  the  climb,  until  we  reached  the  height  of  11,000 


TIIE  WESTERN  SLOPE - THE  NORTHERN  COUNTIES.  339 


or  12,000  feet,  was  very  easy,  as  we  did  not  feel  the  effects  of  the  rare¬ 
fied  air,  and  the  temperature  was  low  enough  to  enable  one  to  use  his 
muscles  actively  without  sensible  perspiration.  The  air  was  still  and 
the  moon  shone  brilliantly  on  the  snow  in  the  gorge  up  which  we  were 
climbing,  while  the  dark  cliffs  on  either  hand  frowned  majestically 
upon  us.  The  most  profound  stillness  prevailed.  Our  way  led  up  a 
sort  of  ravine  or  gorge  between  two  great  buttresses  of  the  mountain, 
one  of  which  comes  down  from  near  the  summit  in  a  southerly  direc¬ 
tion,  the  other  a  little  west  of  south.  The  bottom  of  this  ravine  was 
filled  with  snow  to  a  great  depth;  the  sides  were  formed  by  bare  and 
precipitous  masses  of  black  lava,  rising  in  lofty  cliffs,  topped  by  fantastic 
pinnacles  of  the  same,  hemming  us  in  by  a  wall  from  500  to  1000  feet 
in  height. 

The  ravine  rose  at  first  with  a  moderate  grade,  but  soon  became 
exceedingly  steep,  the  slope  varying  from  30°  to  45°.  The  surface  of 
the  snow  formed  longitudinal  furrows,  three  or  four  feet  in  depth,  with 
ridges  between,  on  which  we  walked,  crossing  from  one  to  the  other, 
or  occasionally  picking  our  way  along  the  edge  of  the  snow,  on  the 
fragments  of  lava  which  had  fallen  from  above  and  which  the  snow  did 


not  rise  high  enough  to  cover.  At  daybreak  we  found  ourselves  pretty 
well  up  the  mountain,  and  the  “Red  Bluffs,”  the  highest  point  of  the 
road  which  was  in  sight,  and  which  is  about  1200  feet  below  the  sum¬ 
mit,  appearing  to  be  close  at  hand,  and  almost  to  overhang  our  path ; 
but  hours  of  hard  climbing  were  required  before  we  should  reach  it. 
The  angle  of  elevation  of  the  ravine  grew  steeper  and  steeper  as  we 
mounted  upwards,  and  the  surface  of  the  snow  rougher  and  rougher, 
so  that  we  were  continually  edging  off  on  to  the  talus  of  rocks  in  the 
hope  of  finding  relief;  but  scrambling  over  the  loose  blocks  of  rough 
lava  was  found  even  more  fatiguing  than  slipping  about  on  the  snow. 

At  length,  with  frequent  stoppages  for  breath,  of  which  the  supply 
seemed  to  grow  very  scanty  after  we  passed  the  altitude  of  10,000  feet 
or  thereabouts,  we  reached,  at  about  10  o’clock,  the  “Red  Bluffs,”  a  low 
wall  formed  by  the  edge  of  a  mass  of  rudely  stratified  volcanic  breccia, 
having  a  reddish  tinge  which  contrasts  strongly  with  the  dark  gray, 
almost  black  color,  of  the  mass  of  the  mountain,  this  dark  shade 
being  intensified  by  contrast  with  the  dazzling  whiteness  of  the  snow. 


340 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


Climbing  this  wall  of  rock,  which  was  effected  without  difficulty,  our 
course  was  now  nearly  at  right-angles  to  our  former  one,  and  over  a 
much  less  steep  slope,  for  a  distance  of  about  two  miles,  which  brought 
us  to  a  rudely  circular  and  nearly  level  area,  evidently  the  bottom  of 
the  ancient  crater,  along  the  eastern  edge  of  which  rises  a  broken  ridge 
with  very  abrupt  sides  forming  the  summit  of  the  mountain,  and  appa¬ 
rently  the  remains  of  the  edge  or  lip  of  the  crater.  In  passing  over 
the  snow-covered  slope  before  reaching  the  level  area,  considerable 
difficulty  was  experienced  in  crossing  with  the  barometers  over  a  wide 
space  on  which  the  snow,  here  almost  icy  in  its  texture,  was  laid  in 
sharp  ridges,  running  in  the  direction  of  the  prevailing  winds  and 
inclining  towards  the  sun,  forming  a  series  of  knife-edges,  with  cre¬ 
vices  between  deep  enough  to  let  one  down  to  the  depth  of  from  one 
to  three  feet.  Across  these  we  had  to  step  as  best  we  could,  knowing 
that  a  single  fall  would  bring  sure  destruction  to  our  instruments. 
The  dogs,  which  accompanied  us  to  the  summit,  gave  most  unmistak¬ 
able  signs  of  entire  disgust  along  this  part  of  the  route.  However, 
this  difficult,  but  not  dangerous,  ground  was  passed,  and  the  level  area 
noticed  above  was  reached  at  11 J  o’clock. 

On  one  side  of  this  fiat  space,  just  at  the  edge  of  the  high  wall,  the 
remains  of  the  edge  of  the  crater,  there  are  several  orifices  from  which 
steam  and  sulphurous  gases  are  constantly  escaping,  and  around  which 
is  a  considerable  deposit  of  sulphur,  some  of  it  being  handsomely  crys¬ 
tallized.  It  is  in  fact  a  small  solfatara,  and  the  last  remains  of  the  once 
mighty  volcanic  agencies  which  have  piled  up  this  now  extinct  volcano 
to  a  height  nearly  4000  feet  greater  than  that  of  Etna,  the  monarch  of 
the  Mediterranean. 

The  summit  of  the  mouutain,  which  is  about  400  feet  above  the  hot 
springs,  was  reached  by  all  the  party  before  12  o’clock,  and  both 
barometers  hung  up  in  safety  in  a  sheltered  nook  about  eighteen  feet 
below  the  highest  point.  The  cold  was  not  intense,  nor  was  the  wind 
severe.  The  barometers,  after  attaining  the  temperature  of  the  air, 
remained  nearly  stationary  at  17.658  inches,  and  the  corresponding 
observations,  taken  6800  feet  lower  down,  indicated  the  same  condition 
at  that  station.  The  thermometer  freely  exposed  to  the  air  stood  at 
27°,  and  the  wet  bulb  had  the  same  temperature  as  the  dry,  a  thin 


THE  WESTERN  SLOPE 


TI1E  NORTHERN  COUNTIES.  341 


cloud  forming  all  the  time  around  us  and  disappearing  as  it  was  car¬ 
ried  away  by  the  breeze. 

The  effects  of  the  great  elevation  were  very  perceptibly  felt  by  some 
of  the  party,  resembling  in  many  respects  those  produced  by  sea-sick¬ 
ness,  and  arising  certainly  in  part  from  nervous  exhaustion  interfering 
with  the  process  of  digestion.  A  disinclination  to  farther  exertion  after 
reaching  the  summit  was  decidedly  perceptible  in  all  the  party,  and 
one  or  two  exhibited,  in  their  very  much  darkened  complexions  and 
bloodshot  eyes,  the  unmistakable  symptoms  of  congestion.  That  this 
condition  was  due  to  the  system  not  having  had  time  to  accommodate 
itself  to  the  diminished  pressure  of  the  atmosphere  was  afterwards 
made  evident  enough  by  the  fact  that,  after  camping  for  some  weeks 
at  an  altitude  of  from  8000  to  10,000  feet,  none  of  the  party  experienced 
any  unpleasant  sensations  in  climbing  to  the  height  of  13,000  feet, 
except,  of  course,  that  muscular  exertion  was  not  so  easy  with  the 
diminished  pressure  at  that  elevation. 

The  view  from  the  summit  of  Mount  Shasta  is  surpassingly  grand; 
but  we  were  not  favored  with  it  in  its  greatest  beauty.  To  have  the 
full  effect  of  the  panorama,  one  should  make  the  ascent  in  the  night, 
so  as  to  stand  upon  the  summit  at  sunrise,  that  being  the  time  when 
the  air  is  clearest  and  the  effect  of  light  and  shade  most  magical,  as 
was  clearly  seen  by  the  party  which  enjoyed  the  sunrise  from  Lassen’s 
Peak.  Besides  this,  it  was  too  late  in  the  season  when  we  ascended, 
and  a  heavy  bank  of  smoke  hung  over  all  the  valleys  at  the  base  of  the 
mountain.  From  out  of  this  obscuring  veil  of  mingled  smoke  and 
dust,  which  took  off'  the  sharpness  of  all  objects  below  5000  or  6000 
feet  in  altitude,  the  summit  of  Lassen’s  Peak  appeared,  distant  about 
seventy  miles,  but  seeming  to  be  close  at  hand  and  to  float  on  the  cloud¬ 
bank  like  an  immense  iceberg  on  the  ocean.  From  the  summit  of 
Lassen’s  Peak  itself,  the  same  thing  was  observed  with  regard  to 
Mount  Shasta,  except  that  the  mass  of  the  latter  being  vastly  greater, 
the  effect  was  of  course  proportionately  increased.  Next  to  the  view 
of  Lassen’s  Peak,  the  most  impressive  part  of  the  panorama  was  that 
presented  by  the  slopes  of  Mount  Shasta  itself,  especially  those  of  the 
east  and  southeast  sides,  down  which  we  could  see  for  thousands  of 
feet  of  almost  sheer  perpendicular  descent,  and  over  which  vast  fields 


342 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


of  snow  alternated  with  jagged,  dark  ridges  and  pinnacles  of  black 
volcanic  rock. 

But  we  were  not  permitted  to  enjoy  any  part  of  the  sublime  pano¬ 
rama  for  a  long  time,  as  the  clouds  began  to  thicken  about  us,  and 
soon  shut  out  our  view  entirely.  In  the  course  of  the  afternoon  a  light 
fall  of  snow  took  place,  which  hastened  our  descent,  as  we  were  not 
sufficiently  at  home  at  that  altitude  to  consider  ourselves  justified  in 
remaining  on  the  summit  until  it  was  too  late  to  reach  our  camp  before 
dark,  especially  as  it  was  highly  desirable  for  the  progress  of  our  work 
in  the  vicinity  that  the  barometers  should  not  he  broken  in  the  descent. 

Leaving  the  summit  at  about  two  o’clock,  Camp  Ross  was  reached  at 
six  without  difficulty  or  accident  either  to  ourselves  or  our  instruments. 
The  snow  being  considerably  softened,  the  steep  slope  was  descended 
by  a  process  half  way  between  sliding  and  floundering,  an  agreeable 
amusement  for  those  who  had  no  barometers  to  take  care  of,  and 
who  were  soon  far  in  advance  of  those  who  were  thus  encumbered. 
During  the  night,  at  camp,  a  strong  wind  prevailed,  and  a  snow  squall 
passed  over,  during  which  about  an  inch  of  snow  fell.  The  next  day 
was  much  clearer  than  the  one  before,  a  slight  fall  of  rain,  the  first 
token  of  the  approach  of  winter,  having  in  a  measure  washed  away  the 
smoke,  and  we  were  strongly  tempted  to  repeat  the  ascent ;  but  want  of 
time  forbade  it,  and  we  descended  to  Strawberry  Flat  the  next  day, 
leaving  one  of  the  party  at  Camp  Ross  to  continue  the  barometrical 
observations,  in  order  to  fix  as  accurately  as  possible  the  elevation  of 
that  station. 

We  have  thus  given  a  more  minute  description  of  our  ascent  of 
Mount  Shasta  than  we  could  afford  space  to  do  for  any  other  mountain 
of  the  many  which  have  been  climbed  by  our  parties,  in  order  to  show 
how  easy  a  matter  it  is,  and  with  the  hope  of  increasing  the  number  of 
those  who  may  be  inclined  to  attempt  this  excursion,  which  even  the 
moderately  practised  mountain-climber  may  undertake  with  success, 
and  which  no  one  who  visits  California  with  the  idea  of  becoming 
acquainted  with  the  noblest  features  of  her  mountain  scenery  should 
omit. 

Some  general  observations  on  the  form  and  geological  structure  of 
the  mountain  and  its  vicinity  may  be  here  appended. 


THE  WESTERN  SLOPE 


THE  NORTHERN  COUNTIES. 


3 


Mount  Shasta  has  been  seen  by  our  parties  from  all  sides,  and  the 
surprising  regularity  of  its  outline  and  its  beautiful  conical  form  have 
again  and  again  excited  our  admiration,  as  they  have  that  of  other 
travellers  in  this  region.  As  seen  from  the  southwest,  however,  this 
symmetiy  is  somewhat  broken  by  the  side-cone  which  rises  on  the 
flanks  of  the  main  mountain,  and  almost  rivals  it  in  its  dimensions.  This 
has  never  yet  been  ascended,  and  is  believed  by  many  to  be  quite 
inaccessible.  Its  sides  appear  to  be  covered  with  loose  volcanic  mate¬ 
rials,  probably  ashes,  lying  at  the  highest  angle  possible  without  sliding 
down.  As  seen  in  the,  sky-outline,  this  angle  is  from  34°  to  35°.  The 
height  of  this  appendage  of  Mount  Shasta  was  estimated  by  us  at  be¬ 


tween  12,500  and  13,000  feet. 

The  annexed  wood-cut  (Fig.  44)  will  show  the  relation  of  the  side- 
cone  to  the  main  mass  of  the  mountain,  and  will  also  exhibit  the  steep- 


Fig.  44. 


a 


OUTLINE  OF  MOUNT  SHASTA. 

Inclination  of  a  b,  27°  to  28°;  of  c  d,  30°  to  31°;  of  e  f,  about  36°. 


ness  of  its  slopes,  as  the  diagram  was  constructed  from  measurements 
of  the  sky-outlines  with  the  clinometer.  It  represents  Mount  Shasta 
as  seen  from  Marble  Mountain,  near  Bass’s  Ranch,  fifty-three  miles 
distant,  and  looking  in  a  direction  of  N.  10°  W.,  magnetic.  Although 
the  upper  part  of  the  cone  is  not  entirely  covered  with  snow,  there 
being  large  patches  of  bare  rock  on  it ;  yet,  as  seen  from  a  great  distance, 
these  all  disappear,  and  the  whole  seems  to  be  one  continuous  sheet  of 
white  above  the  snow-line,  which  is  very  distinctly  marked.  In  this 
diagram,  however,  the  lower  edge  of  the  snow  is  not  seen,  the  inter¬ 
vening  hills  rising  so  as  to  conceal  it.  The  very  great  steepness  of  the 
side-cone  is  apparent. 


344 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


To  judge  from  the  views  of  Mount  Hood,  Mount  Rainier,  Mount 
Baker,  and  the  other  volcanic  cones  of  the  Cascade  Range,  given  in 
the  Pacific  Railroad  Reports,  one  would  conclude  that  these  were  all 
very  much  steeper  than  Mount  Shasta;  but  it  must  be  remembered 
that  these  were  sketched  by  the  eye,  and  that  the  tendency  to  greatly 
exaggerate  slopes  of  this  kind  can  hardly  be  overcome  by  an  artist,  or 
by  any  one  not  correcting  his  conceptions  by  actual  measurements. 
This  has  been  well  illustrated  by  a  comparison  of  the  sketch  of  the 
volcano  of  Cotopaxi,  as  given  by  Humboldt,  and  which  has  figured  in 
all  our  school  geographies  and  geologies  as  having  a  slope  of  48°  ; 
when,  in  reality,  as  measured  on  the  photographs  now  easily  to  he  had 
of  this  cone,  the  average  inclination  of  its  sides  is  found  not  as  great 
as  that  of  Mount  Shasta  in  the  diagram  given  above,  being  in  fact 
between  28°  and  29°,  while  the  greatest  angle,  near  the  summit,  is 
only  32°  (see  J.  I).  Dana,  in  Journal  of  Science  (2),  xxxviii,  427).  As 
seen  from  Lassen’s  Peak,  seventy  miles  distant,  from  which  Mount 
Shasta  bears  N.  48°  30'  W .,  magnetic,  the  angle  of  the  east  side  of  this 
mountain  is  not  less  than  35°,  and  that  of  the  west  slope  26°. 

Our  stay  in  the  vicinity  of  the  mountain  was  so  short,  and  the  diffi¬ 
culty  of  getting  about  the  more  elevated  portion  of  it  so  great,  that 
only  a  general  idea  could  be  obtained  of  its  geological  character  and 
structure.  No  other  rocks  than  those  of  volcanic  origin  were  seen, 
anywhere  from  the  base  to  the  summit  of  this  great  mass.  In  the 
lower  region  about  the  mountain  the  lava  was  of  a  trachytic  character, 
having  a  fine-grained  base,  with  slender  needles  of  hornblende  dissem¬ 
inated  through  it.  Higher  up,  much  basaltic  rock  occurs,  and  the 
overflows  of  this  material  must  have  been  of  immense  thickness,  as  the 
masses  have  a  homogeneous  character  through  a  very  great  vertical 
range.  It  was  surprising  to  notice  how  little  of  scoriae,  ashes,  or 
pumice-like  materials  could  be  found  about  the  mountain.  There  is  a 
heavy  bed  of  volcanic  breccia  near  the  summit,  and  around  the  ancient 
crater;  but,  with  this  exception,  nothing  else  than  dense  and  heavy- 
bedded  lava  was  seen.  Nothing  was  observed,  however,  which  would 
indicate  that  this  vast  pile  of  igneous  material  had  been  formed  in  any 
other  way  than  by  eruption  from  a  crater-like  orifice,  while  the  nearest 
sedimentary  rocks  do  not  show  any  indications  of  disturbance,  as  con- 


THE  WESTERN  SLOPE - THE  NORTHERN  COUNTIES.  345 


nected  with  an  elevation  over  an  area  having*  Mount  Shasta  for  its 
centre.  The  subjects  of  the  composition  and  arrangement  of  the  vol¬ 
canic  materials  of  this,  as  well  as  of  other  regions  in  California,  must 
be  reserved  for  another  volume,  after  a  thorough  examination  shall 
have  been  made  of  the  many  varieties  which  we  have  collected. 

There  are  a  great  number  of  volcanic  cones,  more  or  less  regular  in 
outline,  scattered  over  the  plain  to  the  northwest  of  Mount  Shasta.  These 
give  a  very  peculiar  aspect  to  the  region,  and  add  no  little  to  the  impres¬ 
siveness  of  the  views  one  obtains  of  the  mountain  from  the  neighborhood 
of  Yreka.  One  of  these  conical  mountains,  which  was  much  higher 
than  any  of  the  others,  and  which  lay  close  at  the  western  base  of  Mount 
Shasta,  was  so  beautifully  regular  in  its  outline  that  we  gave  it  the 
name  of  Cone  Mountain.  It  is  a  conspicuous  object  from  Strawberry 
Flat,  and  is  no  insignificant  hill  itself,  being  fully  3000  feet  above  the 
level  of  the  surrounding  plain,  although  utterly  dwarfed  by  its  prox¬ 
imity  to  the  higher  mountain.  This  conical  eminence  shows  no  signs 
of  a  crater  at  the  summit,  but  is  covered  on  the  side  from  which  we 
ascended  it  (the  north)  with  loose  fragments  of  trachyte,  which  grow 
larger  as  wTe  approach  the  summit,  while  at  the  same  time  the  angle  of 
the  slope  increases,  so  that  the  ascent  was  very  difficult  and  not  a  little 
hazardous.  By  mistake,  the  summit  was  not  reached,  but  the  point 
next  west  of  it  (that  next  to  the  left  hand  of  the  highest  peak,  in  the 
sketch);  it  was  2566  feet  above  the  camp  at  Strawberry  Flat,  and 
the  highest  point  was  estimated  at  about  450  feet  above  this.  The 
annexed  wood-cut  (Fig.  45)  shows  the  outline  of  Cone  Mountain,  with¬ 
out  any  exaggeration  of  its  slopes,  as  it  is  a  reproduction  of  a  camera- 
lucida  sketch.  It  is  a  singularly  graceful  and  beautiful  object.  The 
rock  of  which  this  cluster  of  peaks  is  composed  is  a  light-gray,  rather 
fine-grained,  trachytic  material,  with  occasional  small  prismatic  crystals 
of  hornblende  disseminated  through  it. 

For  the  determination  of  the  height  of  Mount  Shasta,  the  barometer 
was  exclusively  relied  on,  and  the  following  system  of  observations  was 
adopted.  As  in  our  other  measurements  of  the  highest  points  of  the 
Sierra,  it  was  our  object  to  have  some  station  selected  as  high  up  as 
possible,  where  a  longer  series  of  observations  could  be  had  than  it 
would  be  convenient  to  make  on  the  very  summit  of  the  mountain  ;  of 

GKOL.  VOL.  I. — 44 


346  GEOLOGY  OF  THE  SIERRA  NEVADA. 

course  it  would  have  been  desirable  to  remain  there  over  night;  but, 
with  our  limited  time  and  means,  only  a  few  hours  during  the  middle 
of  the  day  could  be  spent  in  so  elevated  a  position.  But,  by  having  a 


Fig.  45. 


CONE  MOUNTAIN. 


station  as  high  up  on  the  mountain  as  possible,  of  which  the  height 
could  be  pretty  accurately  fixed  from  the  mean  of  several  days’  observa¬ 
tions,  and  by  having  a  barometer  stationed  there  at  the  same  time  that 
one  was  observed  on  the  summit,  the  horizontal  distance  being  very 
small,  it  is  evident  that  a  considerably  greater  degree  of  precision  wo'uld 
be  likely  to  be  attained  than  if  this  precaution  had  not  been  taken. 

During  the  whole  of  our  stay  in  the  vicinity  of  Mount  Shasta,  which 
was  about  ten  days,  a  station-barometer  was  observed  at  Shasta  City, 
by  Mr.  Esmond,  at  every  hour  from  7  a.m.  to  10  p.m.  The  next  sta¬ 
tion  was  at  Strawberry  Valley,  at  the  base  of  the  mountain,  about  ten 
miles  from  the  summit,  in  a  direct  line,  and  the  third  one  was  at  Camp 
Boss,  at  the  base  of  the  snow-line,  the  elevations  of  each  of  these  sta¬ 
tions  being  respectively  about  1160,  3570,  and  7630  feet.  The  heights 
of  these  points  were  determined  by  a  series  of  simultaneous  hourly 


THE  WESTERN  SLOPE 


THE  NORTH/ERN  COUNTIES.  347 


observations  extending  over  three  days  at  each  station.  To  fix  the 
elevation  of  Shasta  City,  stations  were  selected  at  two  intermediate 
points  between  that  place  and  Sacramento,  namely,  Red  Bluff  and 
Marysville,  the  elevation  of  Dr.  Logan’s  barometer  at  Sacramento 
being  taken  from  Major  Williamson’s  computations  of  a  long  series  of 
observations  made  at  that  city.  The  following  table  gives  the  results 
obtained  : 


Station. 

Sacramento,  .... 
Marysville,  .... 
Red  Bluff,  .... 
Shasta  City,  .... 
Strawberry  Flat,  . 

Camp  Ross,  .... 
Summit  Station, 

Highest  point  of  Mount  Shasta, 


Height  above  next 
lower  station. 

78.3 

237.6 

778.3 

2407.8 

4061.6 

6795.3 

18.0 


I  leight  above 
low  tide. 

65. 

143.7 

381.3 

1159.6 

3567.4 

7629.0 

14.424.3 

14.442.3 


Or,  in  round  numbers,  14,440  feet  above  mean-tide. 

The  direct  calculation  of  the  observations  at  the  summit,  as  com¬ 
pared  with  the  corresponding  one  at  the  same  hour  at  Sacramento  by 
Dr.  Logan,  gave  as  the  height  of  Mount  Shasta  14,401.3  feet,  which  is 
a  closer  approximation  than  should  be  expected  from  observations  taken 
so  far  apart.  In  the  volume  of  Physical  Geography,  forming  a  portion 
of  the  Final  Report,  the  figures  given  above  may  undergo  some  slight 
modification,  after  a  more  complete  elaboration  of  all  our  barometrical 
observations  shall  have  been  made.  Indeed,  it  is  not  unlikely  that  the 
mountain  may  be  again  ascended  during  the  progress  of  the  Survey, 
in  which  case  Yreka  will  be  made  one  of  the  stations,  the  elevation  of 
this  place  having  been  determined  by  a  long  series  of  observations, 
made  by  Mr.  W.  S.  Moses,  and  worked  out  by  Major  Williamson. 

At  the  time  that  Mount  Shasta  was  visited  and  ascended  by  our 
party,  it  was  supposed  that  it  was  the  most  elevated  point  in  California, 
there  being  nothing  then  known  of  the  high  region  of  the  Sierra  Ne¬ 
vada  at  the  head  of  King’s  and  Kaweah  Rivers,  between  latitudes  36° 
and  37°.  It  was  attempted  to  be  shown,  in  a  paper  read  before  the 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


348 


California  Academy,  and  published  in  the  second  volume  of  their  Pro¬ 
ceedings,  that,  if  Mount  Shasta  was  the  highest  mountain  of  the  Sierra 
Nevada  and  Cascade  Ranges,  it  was  very  probably  the  highest  point  in 
the  United  States.  It  was  pretty  satisfactorily  made  out  that  Mount 
Shasta  is  higher  than  any  of  the  lofty  volcanic  cones  to  the  north, 
namely,  Mounts  Pitt,  Hood,  St.  Helens,  Adams,  Rainier,  and  Baker, 
although  it  is  the  almost  universal  opinion  of  the  people  of  Oregon 
and  Washington  Territory  that  Mount  Hood  is  much  higher  than  any 
other  peak  on  the  coast.  An  easy  explanation  will  be  found  for  the 
exaggerated  opinion  of  the  height  of  Hood  as  compared  with  Shasta, 
in  the  circumstance  that  persons  do  not  ordinarily  take  into  account  the 
higher  latitude  of  the  volcanic  peaks  of  Oregon,  the  greater  precipitation 
of  moisture  in  that  region,  and  the  consequently  much  lower  descent 
of  the  snow  line,  which  would  have  a  very  great  effect  in  biasing  the 
opinion  of  an  unskilled  observer,  and  leading  to  an  overestimate  of  the 
more  northern  summits.  The  converse  of  this  has  happened  in  the 
more  southern  portion  of  California,  where  the  comparatively  small 
quantity  of  snow  on  the  Sierra  has  entirely  diverted  attention  from  the 
great  elevation  of  the  range  in  that  region.  We  may  still  maintain,  as 
being  probably  true,  and  certainly  so,  as  far  as  actual  measurements 
made  up  to  the  present  time  show,  that  Mount  Shasta  is  higher  than 
any  of  the  volcanic  peaks  to  the  north,  in  the  Cascade  Range,  although 
inferior  in  elevation  to  one  or  more  of  the  great  granitic  masses  of  the 
Sierra  Nevada  in  the  central  part  of  the  State. 

In  regard  to  the  height  of  Mount  Shasta  as  compared  with  that  of 
the  loftiest  peaks  of  the  Rocky  Mountain  Ranges,  some  additional 
light  has  been  given  by  the  valuable  series  of  observations  made  by 
Dr.  Parry,  in  1862,  elaborated  by  Dr.  Engelmann,  but  not  published 
until  May,  1863  (see  Trans.  Acad,  of  Science  of  St.  Louis,  Vol.  II, 
page  120).  From  this  paper  it  appears  that  Pike’s  Peak  has  an  eleva¬ 
tion  of  14,216  feet  above  the  sea,  and  that  Gray’s  Peak,  southwest  of 
Empire  City,  is  14,245  feet.  This  last  is  the  highest  point  yet  mea¬ 
sured  in  the  Rocky  Mountains,  so  that  Mount  Shasta,  as  yet,  maintains 
its  supremacy  over  the  peaks  of  that  region.  But  Dr.  Parry  states 
that  he  is  confident  that  there  are  summits  in  the  Rocky  Mountain 
chain  still  higher  than  those  measured  by  him,  and  which  may  reach 


THE  WESTERN  SLOPE - THE  NORTHERN  COUNTIES.  349 


15,000  feet  or  more.  lie  does  not,  however,  specify  where  these  lofty 
peaks  are  situated,  or  give  the  reasons  for  supposing  them  to  he  15,000 
feet  or  more  in  elevation.  No  doubt,  since  Colorado  is  so  rapidly  in¬ 
creasing  in  population,  we  shall  have  before  long  a  more  extended 
series  of  observations,  and  possibly  the  lofty  summits  of  the  Sierra 
may  have  to  yield  the  palm  to  the  more  eastern  peaks.  It  should  be 
remembered,  however,  as  Dr.  Engelmann  himself  does  not  fail  to 
notice,  that  a  considerable  element  of  uncertainty  enters  into  the 
results  obtained  by  observations  with  a  single  barometer,  calculated 
with  reference  to  a  station  separated  from  it  by  fifteen  degrees  of  lon¬ 
gitude.  It  is  to  be  hoped  that,  if  not  already  done,  one  or  more  perma¬ 
nent  barometrical  stations  will  soon  be  established  at  the  base  of  the 
Rocky  Mountains,  furnished  with  carefully  compared  instruments  and 
good  observers,  so  that  it  may  be  possible  for  future  parties  seeking 
for  Dr.  Parry’s  15,000-foot  peaks,  to  refer  their  observations  to  a  base 
near  at  hand,  of  which  the  elevation  may  have  been  fixed  by  at  least  a 
series  of  a  year’s  duration. 

Previous  to  the  measurements  of  the  Geological  Survey,  there  had 
been  great  uncertainty  in  regard  to  the  height  of  Mount  Shasta.  It  had 
been  variously  estimated  at  from  14,000  to  18,000  feet.  Lieutenant 
Wilkes,  of  the  Exploring  Expedition,  says  “it  is  said  to  be  14,350  feet; 
but  Lieutenant  Emmons  thinks  it  is  not  so  high*”  Where  these  figures 
and  those  given  by  other  authorities,  especially  the  editor  of  “  Colton’s 
.Atlas”  and  the  author  of  the  article  “  California,”  in  the  “  New  Ameri¬ 
can  Cyclopaedia,”  came  from,  namely,  14,390  feet,  we  have  been  entirely 
unable  to  ascertain.  It  is  certainly  a  very  close  approximation,  but 
whether  a  lucky  guess,  or  the  result  of  some  measurement  of  which  the 
record  cannot  be  traced,  we  are  unable,  at  present,  to  state.  Naturally 
enough,  the  general  opinion  in  California  was,  that  the  mountain  was 
much  higher  than  our  measurements  have  made  it ;  just  as  now  Mount 
Hood  is  firmly  believed,  by  many,  to  be  from  17,000  to  18,000  feet 
high,  although  the  only  actual  measurement  made  of  it,  a  rough  one, 
no  doubt,  puts  it  at  11,934  feet.* 

Having  devoted  as  much  space  as  seems  proper  to  Mount  Shasta 


*  See  Proceedings  of  the  California  Academy  of  Natural  Sciences,  vol.  ii,  page  221 


350 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


and  its  vicinity,  we  will  next  take  up  the  region  on  the  north  side  of  it, 
following:  the  route  of  Messrs.  Brewer  and  King;  to  Yreka. 

About  four  miles  north  of  Fort  Crook,  Fall  River  has  its  source  in 
a  few  very  copious  springs,  the  main  river  issuing  from  a  single  one. 
This  is  a  characteristic  feature  of  the  region  near  the  high  lava  cones, 
and  was  noticed  in  an  eminent  degree  about  Lassen's  Peak.  The 
water  sinks  about  the  summits,  and  issues  at  a  lower  altitude  from 
between  the  lava  Hows.  On  both  the  northern  and  southern  slopes  of 
Lassen’s  Peak,  especially  the  former,  there  are  numerous  very  copious 
springs  of  this  character,  between  the  altitudes  of  6000  and  7500  feet; 
but  neither  springs  nor  streams  were  observed  above  the  last-mentioned 
height.  They  occur  also  both  north  and  south  of  Mount  Shasta,  the 
source  of  Fall  River  on’  the  southeast  of  the  mountain  being  the  most 


marked.  On  the  north  side,  near  Hurd’s  Ranch,  in  Big  Shasta  Valley, 
the  Shasta  River  issues  in  the  same  way  from  the  rocks,  as  a  large 
stream. 

In  going  northwest  from  Fort  Crook  to  Yreka  the  road  passes  over 
a  plain  to  the  Yew  York  Ranch,  twelve  miles  from  the  mouth  of  Fall 
River,  and  there  begins  the  gentle  ascent  of  the  great  lava  tables  which 
lie  along  the  southeastern  flank  of  the  mountain.  The  rock  is  gene¬ 
rally  basaltic,  that  near  the  surface  of  each  flow  or  lava  stream  being 
often  porous.  It  decomposes  and  forms  a  loamy  soil,  which  supports  a 
growth  of  rather  heavy  timber;  but  in  places  where  the  soil  is  thinner 
and  consequently  drier,  the  trees  are  replaced  by  chaparral.  But  few 
streams  flow  over  these  lava  slopes ;  most  of  the  water  sinks,  and 
issues  in  large  springs  below;  in  consequence,  grass  and  forage  are  not 
abundant  over  this  region,  except  on  occasional  moist  grassy  flats. 

Elk  Valley  is  barren,  the  soil  being  a  volcanic  sand,  supporting  a 
scattered  growth  of  low  shrubs,  chiefly  Linosyris.  It  has  an  altitude  of 
3751  feet,  and  may  be  considered  as  the  base  of  the  cone  of  Mount 
Shasta.  The  views  of  that  mountain  from  this  valley  are  among  the 
grandest,  if  not  the  very  finest,  which  can  be  had.  It  bears  from  here 
Y.  58°  W.,  and  has  the  form  of  a  perfect  cone,  both  slopes  being  very 
steep,  as  seen  in  the  sky-outline,  and  the  line  of  vegetation  very  dis¬ 
tinctly  marked,  extending  above  the  lowest  of  the  snow-banks,  even 
on  this  side. 


THE  WESTERN  SLOPE - THE  NORTHERN  COUNTIES.  351 


A  resident  hunter  states  that  there  are  extensive  caves  under  the  lava 
near  Elk  Valley.  He  had  never  explored  them  fully,  but  describes 
them  as  similar  to  those  of  Ilat  Creek.  He  also  stated  that  glacial 
markings  occur  on  Mount  Shasta,  along  its  eastern  and  southeastern 
slopes,  at  the  upper  edge  of  the  timber,  where  he  describes  the  scratches 
and  polished  surface  as  existing  on  an  extensive  scale.  He  also  men¬ 
tioned  that  similar  phenomena  were  to  be  seen  on  the  high  peak  east 
of  Mount  Shasta. 

From  Pilgrim  Camp  to  the  summit  of  the  pass  is  about  twelve  miles, 
the  ascent  being  a  gentle  one  up  the  lava  slopes,  and  the  summit 
broad,  the  road  passing  for  about  two  miles  over  a  nearly  level  plateau. 
The  highest  point  is  about  N.  53°  E.  of  the  summit  of  Mount  Shasta. 
From  this  plateau  the  views  of  the  mountain  are  grand  in  the  extreme, 
the  slopes  appearing  very  steep  and  the  apex  exceedingly  sharp.  Large 
fields  of  snow  extend  downwards  for  6000  feet  below  the  summit, 
broken  by  enormous  fissures,  like  the  “  crevasses”  of  the  glaciers ; 
there  are  extensive  slopes  lying  at  an  angle  of  from  30°  to  40°,  too  high 
an  angle  for  the  snow  to  remain  without  becoming  extensively  fissured, 
although  no  real  glaciers  are  formed,  as  there  would  be,  undoubtedly,  if 
rain  and  snow  fell  during  the  summer. 


At  the  elevation  of  the  summit  of  the  pass,  which  is  about  6300  feet, 
the  sky  was  of  the  most  intense  blue,  and  a  few  light  clouds  were 
observed  clinging  to  the  summit  of  the  mountain.  From  the  pass,  the 
descent  to  Shasta  Valley  is  more  abrupt  than  it  was  on  the  south ;  the 
rocks,  however,  are  of  the  same  character  on  both  sides. 

Under  one  of  the  tables  of  the  north  slope  of  the  pass  there  is  a 
cavern  known  as  “  Pluto’s  Cave;”  it  is  about  four  miles  north  of 
Hurd’s  Ranch.  The  surface  of  the  lava  table  in  the  vicinity  of  the 
cave  has  a  gentle  slope  to  the  north,  is  very  rough,  and  is  raised  into 
numerous  domes  or  “  blisters;”  the  soil  upon  it  is  thin  and  dry.  The 
cavern  is  a  long  gallery  extending  under  this  table,  now  open  for  about 
a  mile  in  a  north-northwest  direction.  Near  the  entrance  the  roof  has 
fallen  in  several  places;  but,  otherwise,  the  gallery  is  continuous,  and 
it  has  a  width  varying  from  twenty  to  fifty  feet,  the  height  being  in 
some  places  as  much  as  sixty  feet.  Throughout  most  of  its  extent  the 
cavity  is  beautifully  arched,  having  a  section  resembling  that  of  an  egg 


352 


GEOLOGY  OF  TIIE  SIERRA  NEVADA. 


set  up  on  its  smaller  end.  The  rock  at  the  top  and  sides  often  has  a 
concentric  structure  parallel  with  the  sides  of  the  arch.  In  places 
there  are  considerable  quantities  of  spongy  lava,  which  seems  to  have 
oozed  from  the  sides  in  a  frothy  state.  The  whole  appearance  of  the 
place  is  that  of  a  cavity  produced  by  the  flowing  out  of  the  liquid  lava 
after  the  sides  and  top  had  become  consolidated.  The  gallery  doubt¬ 
less  extends  much  farther,  but  the  north  end  has  become  blocked  up  by 
fallen  rock. 

Shasta  Valley,  on  the  north  side  of  Mount  Shasta,  like  the  Pitt 
Valley,  is  a  lava  plain,  and  most  of  it  rather  barren,  although  there  are 
some  fertile  spots  on  it.  It  has  an  altitude  of  3087  feet  above  the  sea- 
level.  Rising  from  this  plain  are  an  immense  number  of  conical  hills 
of  volcanic  materials,  most  of  them  but  a  few  hundred  feet  high ;  they 
give  the  region  a  very  peculiar  and  striking  appearance. 

In  the  vicinity  of  Yreka,  ou  the  western  edge  of  the  Shasta  Valley, 
are  low  hills  of  sandstone,  of  which  the  strata  are  horizontal,  or  have 
a  low  dip  east  towards  the  plain.  These  sandstones  rest  on  the  edges 
of  the  auriferous  slates  which  lie  west  of  the  valley ;  they  are  very 
coarse,  and  have  beds  of  conglomerate  interstratified  with  them.  These 
rocks  are  probably  of  Cretaceous  age,  although  no  fossils  were  found 
in  this  immediate  vicinity. 

On  passing  to  the  northeast  of  Yreka,  the  sandstones  interstratified 
with  shales  again  occur,  about  six  miles  from  town,  and  they  extend 
from  here  nearly  to  the  Klamath  River.  They  are  probably  continu¬ 
ous  to  Cottonwood  Creek,  but  they  are  covered  for  a  part  of  the  dis¬ 
tance  with  an  overflow  of  lava.  Cretaceous  fossils  are  abundant  six  to 
ten  miles  northeast  of  Yreka,  where  the  strata  have  a  low  dip  under 
the  plain,  and  appear  to  be  covered  with  the  volcanic  rocks  farther 
east.  In  two  places  well-defined  dykes  of  basaltic  lava  were  observed 
cutting  .these  strata;  they  were  but  a  few  feet  thick,  and  the  shales 
were  scarcely  altered  along  the  line  of  junction,  although  the  stratifica¬ 
tion  was  somewhat  disturbed.  Before  reaching  the  Klamath  River, 
the  road  from  Yreka  passes  among  hills  of  basaltic  lava,  which  cuts 
through  the  sandstones,  and  rises  in  considerable  elevations,  having  in 
places  a  columnar  structure.  At  the  river,  near  the  ferry,  the  lava  is 


THE  WESTERN  SLOPE 


THE  NORTHERN  COUNTIES.  353 


seen  in  places  to  have  had  a  decided  metamorphic  action  on  the  adja¬ 
cent  stratified  rocks. 

Cottonwood  Creek  runs  nearly  south  from  the  summit  of  the  Siski¬ 
you  Mountains  to  the  Klamath  River,  a  distance  of  about  thirteen  miles. 
The  valley,  which  is  about  ten  miles  long,  is  excavated  in  the  softer 
and  unaltered  Cretaceous  strata,  having  on  either  side  harder  rocks, 
namely,  the  auriferous  slates  on  the  west,  and  the  modern  volcanic  on 
the  east.  About  a  mile  from  the  mouth  of  the  valley  is  the  town  of 
Cottonwood  (officially  known  as  Henley),  and  a  section  was  examined 
across  it  at  this  point. 

On  the  west  of  the  town,  the  mountains  of  auriferous  slate  rise  to  the 
height  of  3000  feet  above  the  valley,  or  about  5000  above  the  sea. 
Resting  on  these  unconformably,  are  fossiliferous  Cretaceous  strata, 
which  extend  up  as  high  as  1800  feet  above  the  valley ;  the  relative 
position  of  these  rocks  may  be  seen  in  the  ravines  called  Rancherie 
Creek  and  Rocky  Gulch. 

The  auriferous  slates  are  much  contorted,  but  generally  stand  nearly 
vertical,  and  contain  a  narrow  belt  of  limestone,  which  is  well  seen  in 
the  canons.  Resting  on  the  edges  of  these  slates,  are  coarse  conglom¬ 
erates  in  thick  beds,  then  follow  sandstones,  some  beds  of  which  are 
highly  fossiliferous,  the  fossils  not  being,  however,  in  a  very  good  state 
of  preservation.  Ascending  in  the  series  the  conglomerates  almost 
cease,  the  sandstones  become  less  abundant  and  shales  take  their  places. 
It  is  in  these  shaly  strata  that  the  most  of  the  Cottonwood  Valley  is 
excavated ;  they  are  occasionally  cut  by  a  few  dykes  of  lava.  On  the 
east  side  of  the  valley,  as  we  rise  in  the  series,  we  observe  a  great 
thickness  of  shales  and  sandstones  interstratified  with  each  other. 
These  rocks  contain  but  few  fossils,  except  silicified  wood,  which  is 
abundant  in  certain  strata.  The  shales  sometimes  contain  concretions, 
or  imperfectly  formed  beds  of  argillaceous  limestone,  resembling  the 
hydraulic  cement-rock  of  the  Cretaceous  series  in  the  region  farther 
south.  As  we  ascend  the  hills  to  the  east  of  the  valley,  and  at  the 
same  time  rise  to  higher  beds  in  the  geological  order  of  succession,  we 
find  the  latter  more  and  more  disturbed  and  cut  by  injections  of  lava 
and  finally  covered  by  it.  Near  the  junction,  and  along  the  hills  where 
the  metamorphism  commences,  the  shales  contain  much  silicified  wood, 


GEOL.  VOL.  I. — 45 


354 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


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of  which  many  specimens  are  most  beautifully  preserved.  No  detailed 
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and  the  Plantanaceaz  appear  to  be  best  represented  among  them.  Some 

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southeast  with  the  great  volcanic  belt  of 
Mount  Shasta. 

The  annexed  wood-cut  (Fig.  46)  will 
give  an  idea  of  the  section  which  has 
just  been  described.  The  dip  of  the 
fossiliferous  rocks  is  to  the  northeast  at 
an  angle  of  from  15°  to  35°. 

In  passing  up  the  valley  of  the  Cot¬ 
tonwood,  the  Cretaceous  rocks  are  found 
to  be  everywhere  disturbed,  the  strata 
being  much  broken  and  sometimes  cut 
by  volcanic  dykes ;  the  dip  is  generally 
to  the  northeast.  On  ascending  in  the  se¬ 
ries,  and  at  the  same  time  rising  on  to  the 
Siskiyou  Range,  the  sandstones  become 
|  pq  softer,  and  have  a  smaller  dip  to  the  east, 
generally  less  than  20°.  Near  the  sum¬ 
mit  of  the  pass,  we  cross  two  belts  of 
3  %  ~  metamorphic  rock  cutting  the  sandstones 
having  the  appearance  as  if  the  strata 


THE  WESTERN  SLOPE - THE  NORTHERN  COUNTIES.  355 


had  been  fissured  and  had  then  undergone  alteration  along  the  lines  of 
the  fissures,  in  the  manner  indicated  in  the  accompanying  wood-cut 
(Fig.  47).  These  belts  of  altered  rock  (5,  b)  run  northwest  and  south¬ 
east,  nearly  parallel  with  the  strike  of 
the  strata  (a,  a) ;  they  are  interesting  as 
illustrating  the  manner  in  which  metal¬ 
liferous  veins  beffin  to  be  formed  in 

O 

sedimentary  rocks.  Had  the  thermal 
waters  by  which  these  changes  were 
effected  been  impregnated  with  metallic  salts,  we  should  have  had  here 
a  metalliferous  deposit  of  more  or  less  extent  and  value,  according  to 
the  character  of  the  solution  and  the  length  of  time  the  operation  was 
permitted  to  go  on  without  permanent  interruption. 

At  the  head  of  Cottonwood  Creek,  the  Siskiyou  Mountains  rise  to  the 
height  of  from  5000  to  6000  feet,  and  a  few  miles  farther  west  there  is  a 
peak  which  is  probably  over  7000  feet  high,  as  it  has  patches  of  snow 
on  it  during  the  whole  summer.  A  point  was  ascended  in  this  range, 
which  bore  S.  28J°  W.  from  Mount  Pitt,  and  R.  26°  W.  from  Mount 
Shasta.  This  commanded  a  wide  view.  The  Cretaceous  sandstones 
appeared  to  pass  through  the  chain,  a  short  distance  east  of  the  pass, 
and  then  to  extend  far  northwest  into  Oregon,  forming  a  table  west  of 
Mount  Pitt,  deeply  cut  by  canons,  and  mostly  destitute  of  forests.  It 
is  not  impossible,  however,  that  this  is  a  volcanic  belt.  Rising  above 
and  beyond  it  is  Mount  Pitt,  a  more  regular  cone  than  any  seen  in 
California,  among  the  highest  mountains ;  its  sides  are  very  steep  and 
apparently  covered  by  loose  detrital  materials,  such  as  ashes  or  cinders. 
The  upper  limit  of  trees  is  most  beautifully  marked  upon  it.  It  appears 
to  be  about  10,000  feet  in  height. 

The  annexed  wood-cut  (Fig.  48) 
shows  the  outline  of  this  cone,  with 
the  exact  angles  of  the  sides,  as 
measured  by  the  clinometer.  The 
eastern  slope  makes  an  angle  of  23° 
with  the  horizon ;  the  western  of  26°. 

The  crest  of  the  Siskiyou  Mountains  is  of  tine-grained  granite,  with 
some  hornblende  disseminated  through  a  portion  of  it.  In  some  places 


Fig.  48. 


Fig.  47. 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


356 


it  is  quite  destitute  of  mica,  being  entirely  made  up  of  quartz  and 
feldspar. 

A  rapid  reconnaissance  was  made  of  the  region  between  Yreka  and 
the  Pacific  coast,  Messrs.  Brewer  and  King  passing  over  the  principal 
roads  or  trails,  by  way  of  Deadwood,  Fort  Jones,  Scott’s  Bar,  Happy 
Camp,  Waldo,  Rockland,  and  Altaville,  to  Crescent  City. 

Directly  west  of  Yreka  the  mountains  rise  rather  abruptly  and  are 
much  furrowed  by  deep  canons.  They  consist  chiefly  of  the  auriferous 
slates,  evidently  a  continuation  of  those  of  the  Sierra  Nevada  proper. 
Near  the  town  the  slates  contain  two  beds  of  metamorpliic  limestone, 
much  contorted  and  of  a  slaty  character.  The  slates  and  limestones 
have  a  general  strike  nearly  north  and  south,  and  a  high  dip  to  the 
east,  and  both  rocks  contain  quartz  veins.  Placer-mining  is  carried  on 
extensively  in  all  the  canons  and  gulches.  The  same  kind  of  rocks, 
with  the  same  dip  and  strike,  are  seen  in  passing  up  Greenhorn  Creek, 
and  quartz  veins  are  numerous.  Until  lately,  these  have  had  but  little 
attention  paid  to  them;  but  they  will,  very  probably,  repay  a  careful 
prospecting. 

From  Greenhorn  Creek,  the  road  crosses  a  low  pass  to  Cherry 
Creek,  in  travelling  down  which,  in  a  southwest  direction,  the  Salmon 
Mountains  were  seen  in  front;  these  are  very  high  and  rough,  and 
have  patches  of  snow  on  their  sides.  The  rock  was  everywhere  of  the 
auriferous  slate  formation,  large  masses  of  which  dipped  to  the  west, 
however.  Below  Deadwood,  where  the  canon  widens,  the  gravels  are 
deeper,  and  in  places  are  worked  by  tunnelling. 

From  Fort  Jones  the  party  travelled  north,  down  Scott  Valley,  for  a 
distance  of  five  or  six  miles.  This  is  a  pretty  and  fertile  valley,  sur¬ 
rounded  by  high  mountains;  those  on  the  west  side  are  grandly  furrowed, 
and  retain  large  patches  of  snow  through  the  summer.  The  trail  then 
crosses  a  high  ridge,  at  least  2000  feet  above  the  river,  which  finds  its 
way  through  a  very  deep  and  steep  canon,  impassable  for  a  road.  The 
crest  of  the  mountain  is  of  granite,  which  is  flanked  by  mica-slate  and 
other  metamorphic  rocks.  Scott’s  Bar  was  formerly  a  locality  of  very 
important  placer-mines  ;  but  they  are  now  mostly  worked  out,  although 
considerable  mining  is  still  carried  on  at  intervals.  The  slates  are  very 
much  contorted,  and  are  traversed  by  quartz  veins;  the  dip  of  the  rock 


TliE  WESTERN  SLOPE - THE  NORTHERN  COUNTIES.  357 


at  the  crossing  of  the  river  is  to  the  southwest.  The  bar  is  three  miles 
above  the  mouth  of  Scott’s  Creek,  and  the  intermediate  space  between 
this  place  and  the  Klamath  is  occupied  by  granitic  and  metamorphic 
rocks.  At  one-fourth  of  a  mile  north  from  the  town  the  granite 
begins,  and  extends  one  mile ;  mica-slates  then  occupy  the  space  to  the 
river,  while  the  high  mountain  on  the  west  is  of  granite.  The  mica- 
slates  continue  down  the  Klamath  for  some  miles;  at  the  mouth  of 


Scott’s  River  they  have  a  strike  of  N.  20°  E.,  and  dip  to  the  west; 
three  miles  further  on  they  run  H.  35°  E.,  but  have  the  same  west¬ 
erly  inclination.  Below  this  they  become  irregular,  and  in  some 
places  have  a  gneissoid  character.  All  the  streams  which  issue  from 
the  mountains  to  the  north  bring  down  almost  exclusively  granite  boul¬ 
ders,  and  the  ridges  which  lie  between  Scott’s  River  and  the  Klamath, 
and  west  of  the  former,  are  very  steep  and  high  and  have  some  patches 
of  snow  on  them.  The  bottom  of  the  canon  of  the  river  is  at  least 
5000  feet  below  the  summit  of  this  range >  and  the  slopes  exceedingly 
steep.  Rich  placers  were  formerly  worked  along  this  portion  of  the 
Klamath,  but  they  are  now  nearly  exhausted,  and  the  town  of  Ham¬ 
burg,  which  a  few  years  ago  was  an  active  mining-camp,  is  now  de¬ 
serted  by  white  men  and  its  site  occupied  by  the  huts  of  the  Indians. 

About  nine  miles  below  the  mouth  of  Scott’s  River,  the  Klamath 
strikes  the  granite,  and  flows  over  this  rock  for  four  miles.  This  belt 
of  granite  stretches  across  the  river  and  appears  to  connect  with  the 
granitic  centre  of  the  Siskiyou  Mountains  on  the  north  and  with  that 
of  Scott’s  Mountain  on  the  south.  The  canon  of  the  Klamath  is  nar¬ 
row  and  without  any  botfom-land,  except  at  Reeves’s  Ranch  in  the 
Sciad  Valley.  Here,  at  an  angle  in  the  river,  the  Sciad  Creek  comes 
in  and  there  is  a  fertile  patch  of  about  150  acres,  this  being  the  most 
valuable  ranch  along  the  river  for  more  than  a  hundred  miles. 

Just  north  of  this  place  are  three  prominent  peaks  of  the  Siskiyou 
Range,  known  as  the  “  Three  Devils,”  one  of  which  was  ascended 
and  ascertained  to  be  3746  feet  above  the  ranch,  and  about  5000  feet 
above  the  sea.  It  was  examined  on  the  south  side  and  found  to  be 
made  up  almost  entirely  of  mica-slate,  with  a  northwest  and  southeast 
strike.  Other  peaks  were  seen  from  the  summit,  some  of  which  are  still 
more  elevated  than  the  one  ascended.  One  in  the  immediate  vicinity 


358 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


was  estimated  at  6000  feet  above  the  sea,  and  there  are  still  higher 
ones  to  the  southwest  of  the  Indian  Valley  Pass.  The  summit  of  the 
Three  Devils  is  entirely  of  granite,  cut  by  enormous  veins  of  the  same 
rock,  but  of  a  lighter  color;  this  granitic  mass  appears  to  extend  to 
the  northeast  as  far  as  the  pass  at  Cottonwood  Creek,  on  the  Jackson¬ 
ville  road.  Along  this  line  there  is  a  wilderness  of  peaks,  many  of 
which  are  higher  than  the  Three  Devils,  a  great  number  being  from 
6000  to  7000  feet  high,  and  some  between  7000  and  8000.  There  is  no 
appearance  of  volcanic  rocks  in  this  chain.  To  the  southeast,  between 
the  Three  Devils  and  Yreka,  sharp  ridges  are  seen,  which  appear  to  be 
from  5000  to  6000  feet  high  and  are  chiefly  made  up  of  slates.  Scott 
Mountains,  between  Scott’s  and  Klamath  Rivers,  and  west  of  the  former, 
are  supposed  to  be  from  6000  to  7000  feet  high;  they  have  patches  of 
snow  on  them  through  the  summer. 

The  Sciad  Creek  has  a  valley  or  canon,  which  may  be  traced  some 
fifteen  or  twenty  miles  in  the  direction  of  N.  56°  E.,  and  another  creek 
comes  in  from  an  exactly  opposite  direction*  heading  far  back  in  the 
mountains  south  of  the  Klamath. 

There  is  a  group  of  very  high  and  rugged  mountains  northwest  of 
Happy  Camp,  belonging  to  the  Siskiyou  Range;  The  culminating 
points  of  these  are  probably  nearly  8000  feet  high,  as  extensive  patches 
of  snow  remain  on  them  during  the  whole  summer.  One  double  peak 
is  especially  conspicuous,  and  is  plainly  visible  from  the  sea-coast  near 
Crescent  City.  At  the  head  of  Indian  Creek,  between  that  and  Sailor 
Diggings,  or  Waldo,  there  is  a  very  considerable  depression  in  the 
chain  of  the  Siskiyou  Mountains. 

The  whole  of  the  region  about  the  junction  of  Del  Norte,  Siskiyou, 
and  Klamath  Counties  is  highly  impressive  in  character,  from  the 
evidence  it  exhibits  of  having  undergone  an  immense  denudation. 
The  great  body  of  the  mountains  has  been  lifted  up  to  a  height  of  from 
6000  to  8000  feet,  not  in  one  continuous  chain,  as  in  the  Sierra  Nevada, 
but  in  a  number  of  irregular  and  independent  masses,  and  these  have 
been  so  cut  up  and  furrowed  by  the  action  of  denuding  forces,  as  to 
leave  a  labyrinth  of  sharp  ridges  and  peaks,  separated  by  deep  canons, 
cut  down  to  a  depth  often  as  great  as  5000  or  6000  feet,  a  large  part  of 
which  can  only  have  been  formed  by  the  gradual  wearing  away  of  the 


THE  WESTERN  SLOPE  — THE  NORTHERN  COUNTIES.  359 


rock,  which  once  occupied  the  space  between  the  walls  of  these  stu¬ 
pendous  ravines. 

The  slates  of  these  mountains  are  universally  auriferous,  and  placers 
exist  in  very  many  of  the  canons.  Quartz-mining  has  been  but  little 
attended  to  here  as  yet,  owing  probably  to  the  roughness  and  inacces¬ 
sibility  of  the  region.  In  passing  down  the  Klamath,  from  Reeves’s 
Ranch  to  Happy  Camp,  after  leaving  the  granite  we  strike  mica-slates, 
which  soon  pass  into  the  ordinary  silicious  and  clay  slates  of  the  Sierra. 
They  have  a  strike  of  about  northwest  and  southeast,  and  dip  some¬ 
times  to  the  northeast,  and  sometimes  in  the  opposite  direction.  The 
distance  from  Reeves’s  Ranch  to  Happy  Camp  is  called  eighteen  miles, 
and  the  slates  are  seen  along  nearly  the  whole  route. 

From  Happy  Camp,  the  road  strikes  north  to  Waldo  or  Sailor  Rig¬ 
gings,  thirty-one  miles  distant;  it  is  about  twenty-one  miles  to  the 
summit  from  the  Klamath,  by  the  trail.  The  road  follows  up  Indian  * 
Creek  for  fifteen  miles,  the  rock  being  all  metamorphic  slate,  often 
very  hard  and  finely  laminated.  These  slates  are  traversed  by  quartz 
veins,  and  placer-mining  is  carried  on  all  along  the  creek.  The  moun¬ 
tains  on  either  hand  are  well  timbered,  more  so  than  the  foot-hills  of 
the  Sierra,  there  being  a  large  proportion  of  oaks  and  other  trees  not 
belonging  to  the  Coniferse;  there  is,  however,  much  pine,  fir,  and 
cedar.  The  chestnut,  or  chinquapin  ( Gastanoysis  chrysophylla ),  abundant 
on  the  Sierra  as  a  bush,  becomes,  on  the  Siskiyou  Mountains,  a  tree  one 
and  a  half  feet  in  diameter  and  from  forty  to  sixty  feet  high. 

Towards  the  highest  point  of  the  road,  the  metamorphic  slates  begin 
to  give  way  to  altered  sandstones,  and  some  serpentine  and  talcose 
rocks  occur.  These  are  all  so  irregularly  disturbed  and  uplieaved,  that 
no  satisfactory  idea  of  their  general  position  could  be  obtained.  The 
summit  of  the  pass  is  5434  feet  above  the  sea.  The  rocks  here  are 
metamorphic,  but  granitic  peaks  rise  much  higher  on  both  sides;  those 
southwest  of  the  pass  are  very  high  and  rugged.  Two  peaks,  bearing 
S.  20°  W.  and  S.  24°  W.,  appear  to  be  fully  8000  feet  high,  and  have 
large  fields  of  snow  upon  them  through  the  year. 

The  descent  from  the  summit  of  the  pass  to  the  head-waters  of  the 
Illinois  River  is  quite  steep,  and  over  metamorphic  rocks  with  much 
serpentine,  granite  boulders  occurring  in  the  stream.  Placer-mining 


360 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


begins  from  1000  to  1500  feet  below  the  summit.  About  Sailor  Dig- 
gings  were  formerly  very  rich  placers,  and  they  are  not  yet  exhausted. 
It  is  stated  that  a  nugget  worth  $3100  was  obtained  a  few  years  ago 
on  Althouse  Creek.  A  quartz-mine,  known  as  the  Enterprise,  is 
worked  about  eight  miles  east  of  Sailor  Diggings.  The  vein  is  well- 
defined,  with  smooth  walls,  from  eight  to  eighteen  inches  thick,  and 
runs  R.  10°  E.,  dipping  to  the  east  at  an  angle  of  50°.  It  is  included 
in  the  metamorphic  sandstone.  The  quartz  is  said  to  yield  $26  a  ton 
as  worked  by  arrastras;  but  it  is  reported  as  having  been  shown  by 
assay  to  be  much  richer. 

In  this  vicinity  are  enormous  masses  of  serpentine,  in  places  stained 
with  copper,  and  we  were  told  that  a  heavy  vein  of  copper  pyrites 
occurs  four  miles  southeast  of  Waldo,  Specimens  of  the  ore  were  seen, 
in  massive  pieces,  but  apparently  not  of  a  high  percentage.  The  cost 
of  getting  the  ore  to  market  from  this  region  will  operate  as  a  serious 
drawback  to  the  development  of  these  mines.  Between  Waldo  and 
the  Enterprise  Mine  there  is  a  plain  or  basin,  which  is  excavated  in  the 
slates,  and  is  six  or  eight  miles  across;  it  is  covered  with  gravel,  some 
of  which  has  paid  well  when  washed  for  gold,  although  the  richest 
deposits  are  in  the  gulches  and  smaller  basins  that  surround  this.  These 
mines  are  in  Josephine  County,  Oregon,  the  State  line  crossing  between 
the  summit  of  the  pass  and  Waldo. 

From  Waldo  there  is  a  road  to  Crescent  City,  where  the  business  of 
this  region  is  transacted,  the  distance  in  a  direct  line  being  about 
thirty-five  miles,  but  called  sixty  by  the  road.  In  passing  across  the 
valley  of  the  Illinois  River,  which  is  five  or  six  miles  wide,  a  dyke  of 
eruptive  basaltic  rock  was  observed  cutting  the  slates;  this  was  the 
only  rock  of  the  kind  seen  in  this  region. 

Between  the  valley  of  the  Illinois  River  and  the  coast,  there  is  a 
great  table  or  plateau,  between  3000  and  4000  feet  high,  with  a  gentle 
slope  to  the  west,  but  cut  up  by  innumerable  canons,  so  that  only 
sharp  ridges  remain  to  indicate  its  original  level ;  this,  of  course,  is  a 
very  rough  and  difficult  country  to  travel  over.  The  rock  is  almost  ex¬ 
clusively  of  a  magnesian  character,  serpentine  predominating.  Where 
the  road  crosses  this  table,  between  the  Illinois  and  Smith’s  Rivers,  it 
has  an  altitude  of  about  3800  feet,  and  from  the  summit  there  is  a  wide 


THE  WESTERN  SLOPE - THE  NORTHERN  COUNTIES.  361 

view  in  all  directions,  extending  east  and  west  from  Mount  Pitt  to  the 
ocean.  From  this  point  the  Siskiyou  Mountain  ranges  present  a  very 
rugged  appearance  ;  these  are  almost  entirely  unknown,  both  geograph¬ 
ically  and  geologically.  It  is  stated  by  explorers  that  the  higher  sum¬ 
mits  are  of  granite,  but  that  mica-slate  and  other  metamorphic  rocks 
occur  high  up  on  their  sides. 

The  elevated  plateau-like  region  of  serpentine  and  other  magnesian 
rocks  appears  to  have  been  formed  from  the  metamorphism  of  the 
sandstones.  The  rock  supports  a  shrubby  vegetation,  with  scattered 
trees,  the  soil  being  very  red  and  ferruginous.  In  some  places  the 
stratification  of  the  mass  is  preserved,  and  the  general  strike  appears 
to  be  northwest  and  southeast.  Small  patches  of  soft  granite  were 
noticed  about  twenty  miles  from  Waldo,  and  a  volcanic  dyke  was  seen 
near  the  Rockland  copper  mines.  The  canons  by  which  this  mass  of 
metamorphic  rock  is  cut  up  are  very  deep  and  have  steep  sides,  many 
of  them  being  over  2000  feet,  and  that  of  the  north  fork  of  Smith’s 
River,  at  Rockland,  over  3000  feet  below  the  general  level  of  the  region. 
These  tremendous  gorges  seem  here,  as  elsewhere  in  the  State,  to  have 
been  formed  exclusively  by  aqueous  erosion.  After  passing  this,  the 
same  character  of  country  continues,  the  rocks  being  almost  entirely 
magnesian,  and  containing  a  great  deal  of  chromic  iron,  which  weath¬ 
ers  out  on  the  surface  like  grains  of  shot,  and  is  called  by  the  people 
in  the  vicinity  “  iron  shot.”  Before  reaching  u  Low  Divide,”  which 
lies  between  Hard  Scrabble  Creek  and  Rowdy  Creek,  a  belt  of  slates, 
shales,  and  sandstones,  is  passed ;  these  rocks  cover  a  width  of  three 
or  four  miles.  They  are  but  little  metamorphosed.  All  the  canons 
and  gulches  in  this  vicinity  are  reported  to  contain  gold,  and,  in  many 
cases,  they  are,  or  have  been,  worked  with  profit*  This  belt  of  aurif¬ 
erous  rocks  stretches  away  to  the  northwest,  and  forms  a  chain  of 
peaks  with  a  very  ragged  outline,  rising  rapidly  in  that  direction ;  but 
to  the  south  it  appears  to  lose  itself  in  the  magnesian  belt.  Hear  Low 
Divide,  the  serpentines  commence  again  and  continue  for  several 
miles  to  the  west.  Along  in  a  line  north  and  south  from  the  Low 
Divide  there  are  quite  a  number  of  copper  claims  and  places  where 
mines  have  been  opened  and  worked  for  this  metal.  There  is  also  a 


GEOL.  VOL.  I. — 46 


362 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


cupriferous  district  four  or  five  miles  farther  east,  near  the  north  fork 
of  Smith’s  River,  called  the  Rockland  District. 

The  Rockland  District  is  about  twenty-four  miles  in  a  direct  line 
from  Crescent  City,  and  thirty-five  by  the  road,  this  being  as  direct  a 
course  as  the  topography  of  the  country  will  allow.  These  mines 
were  discovered  in  1863,  and  a  great  many  claims  were  taken  up  at 
that  time,  over  a  belt  several  miles  long  and  running  in  a  direction  of 
X.  28°  W.  In  this  line  of  outcrop,  and  for  a  distance  of  over  nine 
miles,  masses  of  vitreous  copper  ore  have  been  found  at  short  intervals. 
The  “  Diamond  Mine”  had  done  the  most  work  in  1863,  having  shipped 
nine  tons  and  taken  out  as  much  more  of  very  rich  ore,  chiefly  vitreous 
copper  and  red  oxide,  although  native  copper  and  the  carbonates  are 
also  found.  One  piece  of  native  copper  found  here  is  said  to  have 
weighed  over  100  pounds.  At  the  “  Cruikshank  Mine”  the  same  ores 
occur  as  at  the  Diamond,  with  more  magnetic  oxide  of  iron  and  also 
large  masses  of  native  copper ;  one  of  235  pounds  was  found  during 
the  time  of  the  visit  of  Professor  Brewer,  and  another  of  300  to  400 
pounds  was  reported. 

Xearly  parallel  with  these  outcrops,  on  the  east  side,  a  volcanic  dyke 
runs,  and  is  very  conspicuous  a  short  distance  east  of  the  Ruby  Claim. 
It  approaches  the  copper  lode  nearest  at  the  Cruikshank  Mine,  and 
diverges  from  it  in  both  directions  from  this  point.  At  the  Diamond 
Mine,  it  lies  about  one-third  of  a  mile  east,  and  is  several  hundred  feet 
thick.  It  contains  large  crystals  of  hornblende  and  feldspar,  and  is 
generally  very  hard. 

The  Alta  mining  district,  of  which  the  mining  camp  of  Altaville,  at 
the  Low  Divide,  is  the  centre,  is  about  fifteen  miles  northeast  of  Cres¬ 
cent  City,  in  a  direct  line  and  twenty  by  the  road.  A  considerable 
district  here  is  covered  with  claims ;  but,  owing  to  a  variety  of  opinions 
as  to  the  direction  of  the  lode,  there  is  much  confusion  in  their  location. 
Some  twenty-five  different  companies  were  at  work  in  this  district  in 
the  autumn  of  1863,  either  mining  or  prospecting.  The  mineral  chan¬ 
nel  or  lode  appears  to  run  nearly  north  and  south,  and  there  would 
seem  to  be  two  or  more  parallel  veins.  The  Alta  Mine  was,  in  1863, 
the  most  important,  having  been  the  first  one  worked,  and  having  fur¬ 
nished  over  three-fourths  of  the  ore  shipped  from  the  county  up  to  that 


THE  WESTERN  SLOPE - THE  NORTHERN  COUNTIES.  363 


time.  The  workings  were  then  about  240  feet  deep,  and  more  or  less 
ore  had  been  taken  out  all  the  way  down,  the  lode  varying  in  width 
from  an  inch  to  seven  feet.  The  wall-rock  is  serpentine,  and  white 
talc  accompanies  the  best  deposits  or  bunches  of  ore.  Near  the  surface, 
large  quantities  of  the  carbonates  were  found,  and  lower  down,  a  dark- 
colored  ore,  which  seems  to  be  a  mixture  of  various  sulphurets  and  red 
oxide,  yielding  quite  a  high  percentage  of  the  metal,  as  is  evident  from 
the  returns  of  the  shipments,  which  had,  in  1863,  amounted  to  about 
400  tons,  yielding  from  18.4  to  57.8  per  cent,  of  copper. 

In  1863,  seven  companies  had  made  shipments  from  this  region, 
amounting  in  all  to  somewhat  over  600  tons,  as  nearly  as  could  be 
ascertained.  How  far  these  mines  can  be  relied  on  for  permanent 
working,  at  considerable  depth,  remains  to  be  seen  from  future  devel¬ 
opments.  There  can  be  no  doubt  that  the  surface  indications  are  of  an 
important  character,  and  such  as  would  justify  and  require  careful 
explorations.  The  quantities  of  ore  obtained  in  this  region  are  cer¬ 
tainly  such  as  would  indicate  the  existence  of  an  important  copper- 
producing  district  in  Del  Norte  County. 

From  Altaville  to  Meyer’s,  about  three  miles  west,  serpentine  con¬ 
tinues  to  be  the  prevailing  rock;  but  west  of  Meyer’s,  to  Crescent 
City,  other  metamorphic  rocks  are  met  with,  of  which  the  exposures 
are  few,  the  soil  becoming  deeper  and  supporting  a  heavy  growth  of 
timber.  Near  the  base  of  the  hills  slates  are  seen,  much  contorted 
and  dipping  northeast,  and  along  Smith’s  River  they  resemble  the  au¬ 
riferous  rocks  of  the  Sierra. 

At  and  north  of  Crescent  City,  a  plain  stretches  along  the  ocean  for 
about  twenty  miles,  having  a  width  of  six  or  seven  miles  in  places. 
The  metamorphic  slates  make  their  appearance  along  the  beach,  as  is 
well  seen  about  four  miles  to  the  east  of  the  town,  where  the  sea  washes 
the  base  of  the  hills.  These  slates  continue  south  to  the  mouth  of  the 
Klamath  River,  where,  as  we  are  told,  there  is  an  entire  change  in  the 
character  of  the  formation,  the  metamorphic  rocks  of  the  Coast  Ranges 
coming  down  to  the  sea  at  this  point  and  extending  along  the  shore  far 
to  the  south.  The  auriferous  slates  crop  out  in  reefs  and  on  the  main 
land  near  Crescent  City,  forming  the  promontory  near  which  the  town 
is  built,  and  they  extend  north  for  a  mile  or  more,  where  they  disap¬ 
pear  under  a  covering ^of  Tertiary  sandstone. 


364 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


CHAPTER  X. 

THE  HIGH  SIERRA. 

Section  I. — Preliminary  Remarks. 

Having,  in  the  preceding  chapter,  taken  a  rapid  view  of  the  geology 
of  the  mining  region  of  the  western  slope  of  the  Sierra  Xevada,  we 
pass  now  to  a  description  of  the  general  features  of  the  High  Sierra, 
by  which  term  we  understand  that  portion  of  this  great  chain  which 
lies  above  the  metalliferous  belt  just  described,  forming  the  crest  of  the 
range,  and  the  water-shed  between  the  streams  flowing  west  to  the 
Pacific  Ocean  and  those  which  find  their  way  eastward  into  the  Great 
Basin,  or  some  subordinate  one,  where  they  are  lost  by  evaporation. 
It  is,  however,  the  central  portion  of  the  Sierra  to  which  this  chapter 
will  be  especially  devoted,  for  although  the  range  extends  along  the 
entire  length  of  the  State,  yet  the  most  elevated  and  important  part  of 
it  is  that  which  lies  above  and  to  the  east  of  the  principal  mining  coun¬ 
ties,  or  between  the  parallels  of  36°  and  39°. 

It  is  in  the  central  region  of  the  State  that  this  chain  of  mountains 
exhibits  the  greatest  simplicity  of  structure,  both  topographical  and 
geological,  and  it  is  here  that  it  rises  to  its  highest  elevation,  forming, 
so  far  as  we  know,  the  grandest  mountain  mass  of  the  Xorth  American 
continent.  The  culminating  points  of  this  range  lie  between  the  par¬ 
allels  of  36°  and  37°,  and  towards  its  southern  end;  farther  south  the 
chain  sinks  down  very  rapidly,  while  it  also  declines  in  elevation, 
although  much  more  gradually,  as  we  pass  north  from  the  37th  parallel. 

Our  researches  have  not  yet  been  sufficiently  extensive  to  justify  the 
attempt  to  give  a  systematic  description  of  the  Higher  Sierra :  but  we 
can  present  the  results  of  a  rapid  reconnaissance  of  this  chain,  in  the 
course  of  which  we  have  crossed  over  nearly  all  the  passes  of  import¬ 
ance,  and  have  climbed  to  the  summits  of  a  great  number  of  the  most 
prominent  peaks.  Thoroughly  to  study  out  and  lay  down  on  a  map 
the  details  of  this  vast  mass  of  mountains  will  require  many  years  of 
the  severest  labor. 


THE  HEAD  OF  KERN  AND  KING’S  RIVERS. 


365 


For  convenience  in  the  present  chapter  a  geographical  order  will  be 
followed  in  the  description  of  the  High  Sierra,  beginning  at  the  south¬ 
ern  end  of  the  range,  and  proceeding  towards  the  north.  Should  the 
proposed  volume  of  Physical  Geography  ever  appear,  many  things 
which  are  here  only  briefly  mentioned  will  be  more  thoroughly  elabo¬ 
rated,  after  a  sufficient  store  of  observations  shall  have  been  accuinu- 
lated  to  make  this  possible.  The  candid  reader  of  this  volume  will 
not  fail  to  bear  in  mind  that  we  have  in  the  Sierra  Nevada  a  chain  of 
mountains  nearly  as  extensive  as  the  Alps,  forming  a  portion  only 
of  the  region  confided  to  us  for  examination  ;  and,  when  we  consider 
that  the  number  of  Alpine  explorers  and  of  the  published  volumes  of 
their  results  may  be  counted  by  the  hundreds,  their  researches  extend¬ 
ing  over  nearly  a  century,  we  feel  that  we  need  not  apologize  for  the 
imperfections  of  our  work,  believing,  as  we  do,  that  we  have  done  the 
best  which  our  time  and  means  have  permitted. 


Section  II. — The  Region  about  the  Head  of  Kern  and  King’s 

Rivers. 

During  the  summer  of  1864  an  expedition  was  planned  for  a  recon¬ 
naissance  of  an  entirely  unknown  region  of  the  Sierra  Nevada,  namely, 
the  higher  portions  of  this  great  range  lying  between  the  Yosemite 
trail  to  Mono  Lake,  on  the  north,  and  Walker’s  Pass  on  the  south. 
The  glimpses  of  the  high  peaks  of  this  portion  of  the  Sierra,  obtained 
during  the  clear  winter  weather,  from  Mount  Bullion,  on  the  Mariposa 
Estate,  by  Mr.  King,  had  led  him  to  the  belief  that  here  were  the  most 
elevated  summits  of  the  range;  and  this  fact,  coupled  with  the  circum¬ 
stance  that,  unless  explored  during  this  season  by  the  Geological  Sur¬ 
vey,  this  region  might  long  remain  a  blank  on  the  map  of  California, 
led  to  the  organization  of  a  small  party,  whose  object  should  be  to  make 
as  complete  a  reconnaissance  of  this  portion  of  the  Sierra  as  their  lim¬ 
ited  time  and  means  would  permit. 

The  party  organized  for  this  purpose  consisted  of  Professor  Brewer, 
who  had  charge  of  the  expedition,  Mr.  Hoffmann,  topographer,  Messrs. 
King  and  Gardner,  volunteer  assistants  in  the  geological  and  topo- 


# 


366 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


graphical  departments,  and  Richard  Cotter,  an  indomitable  moun¬ 
tain-climber,  whose  services  were  of  great  value  in  more  than  one 
branch  of  the  work.  As  there  were  many  reports  of  the  presence  of 
hostile  Indians  in  portions  of  the  country  to  be  traversed,  an  escort  of 
soldiers  was  considered  necessary,  and  was  supplied  from  the  United 
States  Military  Station  at  Camp  Babbitt,  near  Visalia,  through  the 
intervention  of  Governor  Low,  and  the  kindness  of  General  Wright,  at 
that  time  in  command  at  San  Francisco. 

The  party  left  Oakland  on  the  24th  of  May,  and  reached  Clark’s 
Ranch,  on  the  Yosemite  trail  from  Mariposa,  where  their  labors  ended, 
August  23d,  having  been  engaged  in  the  work  for  just  three  months. 
The  following  sketch  of  the  explorations  made  during  this  time  is  com¬ 
piled  chiefly  from  Professor  Brewer’s  notes,  with  additions  from  those 
furnished  by  Messrs.  King  and  Gardner.  The  geographical  informa¬ 
tion  obtained  by  the  party  will  be  incorporated  by  Mr.  Hoffmann  in 
the  u  Map  of  Central  California,”  now  in  process  of  construction,  and 
which  will  contain  the  results  of  all  our  work  in  the  Sierra,  from 
Owen’s  Lake  to  Lassen’s  Peak. 

The  route  taken  led  first  through  Pacheco’s  Pass,  across  the  plain  of 
the  San  Joaquin,  to  Visalia,  from  which  point  the  Sierra  was  to  be 
entered.  The  season  was  the  summer  following  the  extraordinarily 
dry  winter  of  1863-4,  a  time  when  there  was  probably  less  snow  on  the 
mountains  than  will  be  found  again  for  many  years  to  come. 

The  dry  and  burnt  up.  plain  of  the  San  Joaquin  was  passed  over 
between  May  30  and  June  6th.  It  was  almost  destitute  of  forage,  and 
entirely  so  for  long  stretches,  thousands  of  dead  cattle  being  seen  by 
the  way.  The  only  green  spot  met  with  was  at  Fresno  City,  with  the 
exception  of  those  produced  by  artificial  irrigation  near  Visalia.  While 
passing  over  this  plain,  many  whirlwinds  were  seen;  often  ten  or  fif¬ 
teen,  and  sometimes  as  many  as  twenty-five  or  thirty,  were  in  sight  at 
once.  The  dust  of  the  plain  was  raised  by  them  into  columns  several 
hundred  feet  high,  and  occasionally  more  than  a  thousand  feet.  These 
pillows  of  dust  sometimes  assumed  the  form  of  slender  columns,  which 
swayed  backwards  and  forwards  like  gigantic  ropes.  At  other  times, 
they  rose  in  hollow,  inverted  cones;  or  a  column  would  expand  into  a 
cone  at  some  distance  from  the  ground.  At  the  junction  of  the  column 


THE  HEAD  OF  KERN  AND  KING’S  RIVERS.  367 

and  the  cone  a  fringe  or  horizontal  cloud  of  dust  would  occasionally  be 
seen,  with  many  fantastic  forms,  in  which  column  and  cone  were  vari¬ 
ously  combined  with  each  other.  These  phenomena  were  observed 
chiefly  between  the  hours  of  10  a.m.  and  2  p.m. 

As  seen  from  the  plain  of  the  San  Joaquin,  the  high  mass  of  moun¬ 
tains  near  Owen’s  Lake  (now  known  to  be  considerably  the  highest 
part  of  the  Sierra)  appeared  to  have  much  less  snow  on  it  than  the 
peaks  about  Mount  Lyell  and  the  region  east  of  the  Yosemite;  the 
much  greater  distance  of  this  high  mass  rendered  it  difficult  to  realize 
its  great  altitude.  The  view  of  the  Coast  Ranges  from  the  plain  was 
also  an  interesting  one.  The  Panoche  Grande,  a  short  distance  south 
of  Yew  Idria,  with  its  broad  summit,  is  the  dominating  elevation, 
being  a  little  higher  than  the  sharp  peak  of  San  Carlos.  The  meta- 
morphic  core  of  the  chain,  dark  with  scattered  trees,  exhibited  a 
marked  contrast  with  the  lighter-colored  and  bare  hills  of  unaltered 
strata  in  front.  These  Tertiary  foot-hills  of  the  Coast  Ranges,  at  this 
season,  presented  a  striking  picture  of  desolation  and  aridity.  They 
are  deeply  furrowed  by  denudation,  and  appear  to  run  out  into  the 
plain  in  a  narrow  point  at  Cantua  Creek,  as  has  already  been  noticed 
in  a  preceding  part  of  this  volume. 

The  trees  on  the  plain  at  King’s  River  form  a  belt  about  four  miles 
wide,  and  this  is  succeeded  by  a  barren,  alkaline  region,  which  con¬ 
tinues  to  the  Four  Creeks.  The  soil  in  places  is  as  crisp  with  alkali 
and  salt,  as  if  it  had  been  frozen  while  saturated  with  water.  Year 
Visalia  is  another  grove  of  beautiful  oaks,  but  of  limited  extent.  It 
was  soon  traversed,  in  going  in  a  northeasterly  direction  towards 
Thomas’s  Mill,  and  was  succeeded  by  a  hard,  clayey  soil,  thrown  up 
into  alternate  hillocks  and  hollows,  popularly  known  as  u  hog-wallows,” 
the  origin  of  which  it  is  not  easy  to  explain.  They  resemble  the  hil¬ 
locks  left  by  the  gradual  decay  of  trees  uprooted  by  the  wind  in  our 
Eastern  forests,  and  the  depressions  between  them  contain  water  in  the 
rainy  season. 

At  a  distance  of  from  five  to  eight  miles  from  the  apparent  base  of 
the  Sierra  is  a  range  of  low,  isolated,  rocky  hills,  which  forms  an 
irregular  belt  of  elevations,  separated  from  the  main  chain  by  an  inter¬ 
vening  plain.  These  hills  are  made  up  of  metamorphic  rocks,  such  as 


368 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


silicious  slates,  altered  sandstones,  and  serpentine,  and  appear  to  be 
the  feeble  representative  of  the  great  metamorphic  belt  of  the  Sierra 
farther  north.  A  line  drawn  through  the  centre  of  the  slates,  from 
Sierra  County  to  the  Fresno  River,  if  continued  to  the  south,  would 
pass  out  into  the  valley  of  the  San  Joaquin.  It  is  certain  that  the  belt 
of  metamorphic  rocks  which  constitutes  the  main  body  of  the  produc¬ 
tive  Gold  Region  of  the  State  narrows  down  almost  to  a  point  south  of 
the  Fresno,  the  area  occupied  by  the  foot-hills  becoming  narrower, 
while  the  edge  of  the  mountains  retreats  to  the  east,  apparently  owing 
to  the  great  diminution  in  thickness  of  the  metamorphic  rocks  which 
form  the  lower  portion  of  the  Sierra  farther  north. 

At  the  base  of  the  Sierra,  on  the  route  from  Visalia  to  Thomas’s 
Mill,  granite  is  met  with,  and  a  scattered  forest  vegetation  commences 
at  the  same  time,  with  some  shrubby  undergrowth.  The  oak($.  Gar- 
ryana)  is  the  most  abundant  tree  ;  but  the  pine  so  commonly  seen  far¬ 
ther  north  in  this  position  (P.  Sabinicma)  is  here  of  rare  occurrence. 
For  a  distance  of  ten  miles  on  the  road,  equal  to  eight  miles  in  a 
straight  line,  from  the  edge  of  the  foot-hills,  thin  belts  of  massive 
black  hornblende-rock,  with  some  mica-slate,  were  observed,  interca¬ 
lated  in  the  granite  ;  these  occupy,  however,  but  a  very  small  portion 
of  the  surface  as  compared  with  the  other  rock. 

The  belt  of  pines  is  entered  quite  suddenly  at  an  elevation  of  from 
3200  to  3500  feet,  and  at  5000  feet  the  forests  are  already  made  up  of 
large  trees.  Thomas’s  Saw-mill  (Camp  164),  at  an  elevation  of  5484 
feet  above  the  sea,  and  about  forty  miles  northeast  of  Visalia,  was  iixed 
on  as  the  base  of  supplies  for  this  expedition.  The  mill  stands  on  the 
edge  of  a  beautiful  meadow,  the  water  from  which  runs  into  King’s 
River.  It  is  surrounded  by  a  magnificent  forest  of  the  usual  coniferous 
trees  found  in  the  Sierra  at  this  altitude,  and  a  little  higher  up  the  Big 
Trees  ( Sequoia  gigantea)  are  abundant.  They  do  not  occur  in  separate 
groves,  as  is  the  case  farther  north,  but  are  scattered  through  the 
forests  at  an  elevation  of  from  6000  to  7000  feet.  They  extend  all  the 
way  from  King’s  to  Kaweali  Rivers,  and  perhaps  farther.  The  largest 
tree  seen  was  106  feet  in  circumference  at  the  base,  and  276  feet  high. 
It  had,  however,  been  burned  on  one  side,  and,  when  entire,  must 
have  had  a  girth  of  from  115  to  120  feet.  It  expands  very  much  at  the 


THE  HEAD  OF  KERN  AND  KING’S  RIVERS. 


369 


base,  and  at  twelve  feet  from  the  ground  was  only  seventy-six  feet  in 
circumference.  Another  noted  tree  in  this  region  is  prostrate  and  hol¬ 
low  ;  it  is  burned  out  so  that  one  can  ride  in  on  horseback  for  a  dis¬ 
tance  of  seventy-six  feet,  and  then  have  room  enough  to  turn  round. 
At  120  feet  from  the  base  this  tree  is  thirteen  feet  in  diameter,  inside 
the  hark.  There  are  an  immense  number  of  the  Big  Trees  in  this 
vicinity  which  are  from  ten  to  fifteen  feet  in  diameter,  and  smaller  ones 
in  abundance,  the  latter  being  cut  up  into  lumber  at  the  saw-mill,  in  a 
manner  entirely  at  variance  with  the  often-repeated  story  of  the  excep¬ 
tional  character  of  this  species.  The  Indians  in  this  region  report  the 
existence  of  a  tree  much  larger  than  either  of  those  noticed  above,  but 
our  party  was  too  much  pressed  for  time  to  go  in  search  of  it. 

About  six  miles  east  of  Thomas’s  Mill,  a  rocky  summit,  called  Bald 
Mountain,  was  ascended  for  the  purpose  of  getting  the  first  idea  of 
the  topography  of  the  unknown  region  about  to  be  visited.  It  was  . 
easy  of  access,  although  7936  feet  high,  and  offered  a  fine  view  of  the 
neighboring  country  and  the  extended  crest  of  the  Sierra.  Its  posi¬ 
tion  was  at  once  seen  to  be  on  the  sreat  elevated  divide  between  the 

o 

waters  of  King’s  River  on  the  north,  and  the  Kaweah  on  the  south. 
This  divide  runs  up  to  the  snowy  mountains  at  the  summit  of  the 
chain,  and  appeared  to  terminate  in  the  highest  group  of  peaks,  some 
twenty-five  or  thirty  miles  distant.  The  ridge  of  the  divide  rose  at 
intervals  into  peaks,  each  one  commanding  the  country  on  either  side 
and  behind  it,  as  well  as  forward  to  the  east  as  far  as  the  next  high 
point  in  that  direction.  About  eight  or  nine  miles  to  the  north,  and 
several  thousand  feet  below,  was  the  canon  of  King’s  River,  which 
seemed  precipitous  and  impassable.  Some  twenty  miles  to  the  north¬ 
east,  this  river  divides  into  two  branches,  and  the  course  of  the  north¬ 
ern  of  these  is  such  that  the  observer  on  the  summit  of  Bald  Moun¬ 
tain  can  look  directly  into  it.  The  view  is  most  impressive.  Granite 
walls  with  buttresses,  pinnacles  and  domes  rise  perpendicularly  from 
three  to  five  thousand  feet  above  the  river,  and  above  these  the  bare 
rocky  slopes  tower  up,  high  above  all  vegetation,  into  regions  of  per¬ 
petual  snow.  Dark  lines  of  trees  wind  up  the  ravines  on  the  mountain 
sides,  becoming  thinner  and  more  scattered,  until  they  disappear  alto- 


GEOL.  VOL.  I. — 47 


370 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


gether,  the  summits  of  the  mountains  rising  far  above  all  vegetation, 
barren,  and  desolate. 

Such  is  the  character  of  the  divide  between  the  main  forks  of  the 
King’s  River,  although  the  southern  side  is  not  as  steep  as  the  north¬ 
ern.  Its  lofty  summit,  everywhere  crested  with  precipices,  presented  an 
insurmountable  barrier,  over  which  our  party  never  succeeded  in  taking 
their  animals.  Just  at  the  junction  of  the  forks,  the  end  of  the  divide 
is  crossed  by  a  broad  red  stripe,  bearing  about  northwest,  and  which 
could  be  seen  appearing  again  on  the  north  side  of  the  canon.  This, 
which  seemed  to  be  a  great  dyke  of  volcanic  rock,  but  which  was  after¬ 
wards  found  to  be  a  vein  of  granite,  led  to  giving  this  divide  the  name 
of  u  Dyke  Ridge.” 

An  attempt  was  first  made  to  reach  the  summit  of  the  Sierra  by 
travelling  up  this  divide,  an  old  Indian  trail  being  discovered  which 
was  followed  for  about  fifteen  miles.  This  trail  led  to  a  point  where 
the  ridge  widened  out  into  a  plateau  occupied  by  a  large  meadow;  a 
number  of  cattle  had  been  driven  here,  and  the  place  was  known  to 
hunters  as  the  u  Rig  Meadows.”  Camp  165  was  intermediate  between 
Thomas’s  and  the  Big  Meadows,  and  was  7480  feet  above  the  sea.  The 
rock  along  the  whole  route  is  granite,  which  has  a  tendency  to  weather 
into  grand,  rounded,  boulder-like  masses.  Near  Camp  165,  it  was 
very  light-colored,  inclosing  an  immense  number  of  bands  of  darker- 
colored  and  finer  materials,  which  were  generally  lenticular  in  shape, 
and  from  a  few  inches  to  several  feet  in  width,  with  their  longer  axes 
parallel.  In  places  the  rock* assumes  a  gneissoid  structure;  but  passes 
gradually  into  the  homogeneous  granite  on  all  sides. 

Camp  166,  about  two  miles  below  the  Big  Meadows,  but  nearly  at 
the  same  altitude,  was  at  an  elevation  of  7827  feet.  Here  the  granite 
is  of  more  uniform  texture  over  large  areas,  and  is  made  up  of  quartz, 
feldspar,  mica,  and  hornblende,  the  last-named  mineral  predominating 
over  the  mica.  The  massive  granite  is  traversed  by  occasional  dykes 
of  a  fine-grained  variety  of  the  same  rock,  and  with  veins  of  milky 
quartz.  Large  areas  of  nearly  level  or  gently  sloping  ground  occur 
here,  covered  with  meadows  or  forests  of  Pinus  contorta ,  and  there  are 
also  extensive  patches  of  bare  rock,  or  of  granitic  sand  derived  from 
its  decomposition.  As  the  granite  decomposes  very  irregularly,  the 


THE  HEAD  OF  KERN  AND  KING’S  RIVERS. 


371 


harder  portions  rise  in  rocky,  rounded  hills,  and  the  softer  are  occupied 
by  small  valleys.  A  series  of  these  grassy  plats,  live  or  six  miles  in 
length,  makes  up  the  Big  Meadows,  and  they  are  drained  in  both 
directions,  namely,  into  the  King’s  and  Kaweah  Rivers.  At  this  alti¬ 
tude  the  sugar  and  pitch  pines,  as  well  as  the  Big  Trees,  are  left  behind, 
and  the  forests  are  made  up  of  the  dark  and  sombre  fir  and  Pinus  con- 
iorta.  Although  it  was  the  month  of  June,  the  thermometer  sank  as 
low  as  16°  at  night,  and  a  snow  storm,  of  three  or  four  hours’  duration, 
occurred. 

Just  east  of  the  Big  Meadows,  and  on  the  summit  of  the  divide,  are 
two  elevations,  to  which  the  name  of  “ Dome  Mountains”  was  given, 
from  the  finely  rounded,  dome-like  sweep  of  their  outlines,  which 
contrast  in  a  striking  manner  with  the  sharpness  of  the  summit  peaks 
behind  them.  On  their  southern  sides  the  forests  rise  in  an  unbroken 
curve  to  their  summits ;  but  on  the  north  side  there  is  a  precipice  for  200 
to  300  feet  below  the  crest,  then  a  short  concave  curve,  and  then  the 
rounded  and  wooded  slope  descending  to  the  King’s  River  Valley.  In 
this  part  of  the  mountains,  as  at  the  Yosemite,  the  granite  exhibits  a 
tendency  to  form  dome-shaped  masses  on  a  grand  scale;  but  on -the 
very  crest  or  summit  range,  it  rises  in  pinnacles,  giving  a  very  different 
character  to  the  scenery,  as  will  be  noticed  farther  on.  .That  one  of 
these  Dome  Mountains  which  was  ascended  was  found  to  be  9825  feet 
high.  Its  summit  was  made  up  of  concentric  layers  or  beds  of  granite 
from  one  to  five  feet  thick,  having  no  trace  of  gneissoidal  structure, 
but  breaking  into  large  rectangular  masses,  sufficiently  smooth  and 
regular  in  form  to  be  used  for  masonry,  without  dressing.  The  north 
slope  of  the  mountain  is  covered  by  immense  masses  of  this  angular 
debris. 

The  peculiar  concentric  or  dome  structure  of  the  granite  in  this  and 
other  portions  of  the  Sierra 
may  be  illustrated  by  the  an¬ 
nexed  wood-cut  (Fig.  49), 
which  represents  the  summit 
of  one  of  these  great  rounded 
masses.  These  give  a  very  peculiar  aspect  to  the  scenery,  and  they 
are  also  of  no  little  interest  in  a  geological  point  of  view.  That  this 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


372 


structure  is  not  the  result  of  the  original  stratification  of  the  rock  is 
evident  from  a  study  of  the  phenomena,  which  do  not  indicate  any¬ 
thing  like  anticlinal  or  synclinal  axes,  or  any  irregular  folding.  The 
curves  are  arranged  strictly  with  reference  to  the  surface  of  the  masses 
of  rock,  showing  clearly  that  they  must  have  been  produced  by  the 
contraction  of  the  material  while  cooling  or  solidifying,  and  also  giving 
very  strongly  the  impression  that,  in  many  places,  we  see  something  of 
the  original  shape  of  the  surface,  as  it  was  when  the  granitic  mass 
assumed  its  present  position.  In  the  canons  between  these  domes,  we 
sometimes  have  large  surfaces  exposed  by  denudation,  and,  as  a  result 
of  the  original  concentric  structure  of  the  rocks  on  each  side,  we  see 
the  great  plates  of  granite  overlapping  each  other  in  the  manner  repre¬ 
sented  in  the  annexed  wood-cut  (Fig.  50). 


Fig.  50. 


Where  considerable  weathering  and  denudation  has  taken  place,  we 
have  picturesque  and  curious  forms  as  the  result;  pyramids  and  pin¬ 
nacles  are  left  standing  on  the  prominent  points,  and  their  bedded 
structure  adds  to  the  peculiar  impression  which  they  give  of  their 
being  works  of  art  rather  than  of  nature.  A  sketch  by  Mr.  Hoffmann, 
taken  above  Camp  169  (Fig.  51),  will  serve  to  illustrate  the  kind  of 
scenery,* which  is  common  in  the  region  of  this  concentrically-bedded 
granite. 

Abundant  traces  of  glacier  action  were  observed  on  and  about  these 
mountains;  but  it  will  be  more  convenient  to  group  together  in  an¬ 
other  place  what  there  is  to  be  said  in  regard  to  the  former  ^existence 
of  glaciers,  on  an  immense  scale,  in  this  part  of  the  Sierra. 

The  route  followed  by  the  party,  in  their  attempt  to  reach  the  sum¬ 
mit,  led  around  the  north  side  of  the  Homes,  over  the  huge  piles  of 


angular  fragments,  and  was  on  this  account  tedious  and  difficult. 
Camp  167  was  made  at  a  point  two  miles  northeast  of  the  Dome,  and 
at  an  altitude  of  8890  feet  above  the  sea.  Camp  168  was  four  or  live 


Fig.  51 


GRANITE  ROCKS  NEAR  CAMP  169. 


miles  southeast  of  the  Dome,  at  a  small  meadow  on  the  divide,  and  at 
an  elevation  of  9569  feet.  Progress  was  necessarily  very  slow,  owing 
to  the  heavy  load  of  provisions  and  instruments  with  which  the  small 
train  of  animals  was  packed,  and  the  extreme  roughness  of  the  region 
travelled  over.  Beyond  the  Domes  the  divide  contracts  to  a  mere 
ridge ;  the  slope  to  the  south,  although  steep,  is  comparatively 
smooth,  and  spreads  out,  towards  its  base,  into  rolling  wooded  spurs, 
between  which  small  brooks  run  down  into  the  Kaweah.  Nearly  all 
these  streams  head  in  little  sedgy  meadows,  whose  bright  green  con¬ 
trasts  beautifully  with  the  deep  shade  of  the  surrounding  forests.  To 
the  north,  the  aspect  of  things  was  different;  instead  of  a  smooth 
slope,  there  was  a  fractured  granite  precipice,  descending  200  feet, 
then  a  slope  of  debris,  and  at  its  foot  two  small  lakes,  forming  the 
headwaters  of  a  stream  which  unites  with  the  south  fork  of  King’s 


'  h" 


374 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


River  a  few  miles  above  the  dvke.  This  stream  was  called  Glacier 
Brook,  from  the  abundant  traces  of  former  glacial  action  in  its  vicinity. 
From  Camp  168  to  the  Big  Meadows  is  only  sixteen  miles;  hut  so  dif¬ 
ficult  was  the  way,  that  it  required  two  days  for  the  party  to  accomplish 
that  distance.  From  this  camp,  and  the  next  (No.  169)  two  miles  far¬ 
ther  up  the  divide,  an  examination  was  made  of  an  interesting  and 
characteristic  feature  in  the  topography  of  this  granitic  region,  and  to 
which  the  name  of  “  The  Kettle”  was  given. 

This  is  a  rocky  amphitheatre  at  the  head  of  a  stream  which  flows 
back  directly  northeast  from  its  source  towards  the  axis  of  the  chain, 
for  a  distance  of  twelve  miles,  and  then  curves  and  enters  King’s  River, 
a  peculiar  and  almost  unique  course  for  a  stream  in  the  Sierra  Nevada. 
The  kettle-like  form  of  the  head  of  this  valley  may  be  seen  from  the 
annexed  section  across  it  transversely,  at  a  distance  of  about  a  mile 
from  its  head  (Fig.  52) ;  it  is  plotted  on  an  equal  scale  of  horizontal 
and  vertical  distances. 


Fig.  52. 

1 3 


SECTION  OF  THE  KETTLE. 


The  northern  rim  (a)  is  about  1100  feet  above  the  bottom  (b) ;  the 
southern  one  ( c )  rises  in  a  sharp  ridge  1606  feet  above  b;  in  some 
places  c  d  is  a  vertical  wall,  in  others  a  steep  slope.  The  distance  from 
a  to  c  is  a  little  less  than  a  mile.  The  Kettle  is  open  at  the  north-north¬ 
east  end,  and  extends  as  a  green  valley  some  six  miles,  to  the  south 
fork  of  King’s  River.  There  are  several  small  domes  and  pinnacles  on 
the  east  side,  and  in  some  places  the  granite  along  the  rim,  forms  a 
parapet,  which  has  a  striking  resemblance  to  an  artificial  structure,  as 
the  rock  is  most  beautifully  and  regularly  bedded,  so  that  the  wall 
seems  to  vie  with  the  most  finished  mason-work  in  execution.  The 
annexed  wood-cut  (Fig.  53)  will  show  the  exact  appearance  of  a  por- 


THE  HEAD  OF  KERN  AND  KING’S  RIVERS. 


375 


tion  of  this  wall,  which  is  in  some  places  so  thin  that  the  light  can  he 
seen  shining  through  between  the  cracks.  It  is  from  eight  to  twenty 
feet  high. 


Fig.  53. 


i 


RIM  OF  THE  KETTLE. 


This  rim  of  the  Kettle  is  a  beautiful  illustration  of  the  concentric  or 
“  dome-structure”  of  the  granite  of  this  region.  The  dotted  lines  in 
figure  52  show  the  bedding  or  lamination  of  the  rock,  in  the  cross  sec¬ 
tion  of  the  whole,  and  figure  54  explains  how  the  parapet  has  been 
formed  by  the  wearing  away  of  a  part 
of  the  concentrically-laminated  gran-  Fls- 

ite  near  the  summit.  This  peculiar 
crater-like  cavity  in  the  granite  is 
typical  of  many  others  seen  after¬ 
wards  in  this  region,  the  origin  of 
which  it  seems  impossible  to  refer  to 
any  ordinary  denudation,  or  to  the 
action  of  glaciers.  These  cavities 
were  all  occupied  by  masses  of  ice, 
as  is  evident  from  the  polish  of  the  interior  walls  and  bottom  of  each 
of  them  ;  but  it  hardly  needs  to  be  added  that  no  glacial  action  could 
have  originally  formed  one  of  these  kettles;  the  most  that  it  could 


376 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


do  would  be  to  scour  out  and  polish  up  the  interior.  This  subject  will 
be  discussed  in  full  at  some  future  time. 

Beyond  the  Kettle,  the  divide  becomes  quite  impassable  for  animals, 
and  nearly  so  for  men.  Several  unsuccessful  trials  were  made  to  pass 
the  barrier  of  nearly  perpendicular  rocks ;  but,  at  last,  a  chink  in  the 
granite  was  found,  through  which  the  party  crawled,  and  proceeded  to 
ascend  Mount  Silliman,  which  is  the  next  high  peak  on  the  divide  and 
about  six  miles  southeast  of  Camp  169.  As  seen  from  the  north  or 
northwest,  Mount  Silliman  appears  like  a  great  lava  or  volcanic  table 
mountain,  with  mural  sides.  A  drawing  from  a  sketch  by  Mr.  Hoff¬ 
mann  (Fig.  55),  will  serve  to  give  an  idea  of  this  prominent  point;  it 


Fig. 


55. 


MOUNT  SILLIMAN. 


was  taken  near  Camp  168.  This  mountain  is  of  granite,  but  of  a 
darker  color  than  the  rock  of  the  surrounding  country ;  it  is  much 
intersected  with  veins  of  granite  of  a  still  deeper  tinge  than  the  main 
body  of  the  rock,  and  portions  of  it  are  reddened  and  discolored  by 


TIIE  HEAD  OF  KERN  AND  KING’S  RIVERS. 


077 

O  l  i 


the  oxidation  of  the  iron  it  contains.  Its  elevation  was  found  to  be 
11,623  feet  above  the  sea.  This  mountain  is  formed  by  the  meeting  of 
two  knife-edges  of  the  main  divide,  forming  the  western  and  northeast¬ 
ern  faces  of  the  peak,  and  inclosing  between  them  a  crater-like  cavity, 
at  least  a  thousand  feet  deep,  the  walls  of  which  present  a  mural  face 
to  the  north  and  slope  off  gradually  to  the  south. 

From  the  summit  of  this  peak  a  magnificent  view  was  obtained  of 
the  crest  of  the  Sierra,  as  well  as  of  the  divide  which  had  been  tra¬ 
versed  by  the  party.  The  region  to  the  east  presented  a  complicated 
system  of  very  sharp  ridges,  rising  here  and  there  into  pinnacles,  appa¬ 
rently  all  of  granite,  with  numerous  immense  circular  amphitheatral 
cavities,  formed  by  sharp  ridges  surrounding  basins,  of  which  one  side 
is  always  broken  away,  and  which  have  exactly  the  appearance  of 
ancient  craters  both  in  form  and  outline.  To  the  west  the  predomi¬ 
nance  of  rounded  or  dome-shaped  mountain  summits  was  most  strik¬ 
ing,  the  whole  country  having  the  appearance  as  if  it  had  suddenly  been 
cooled  or  congealed  while  violently  boiling. 

Camp  170  was  about  seven  miles  north-northeast  of  Ho.  169,  in  the 
valley  of  the  stream  which  flows  from  the  Kettle,  and  at  an  altitude  of 
7408  feet,  which  was  a  lower  point  than  was  afterwards  reached  by 
the  party  for  a  long  time.  The  way  to  this  camp  led  around  the  west 
and  north  sides  of  the  Kettle  over  a  region  exceedingly  difficult  to  tra¬ 
verse,  with  alternating  steep,  naked  slopes  of  granite,  and  thick,  low 
forests.  Some  of  the  ancient  moraines,  piles  of  angular  fragments  of 
granite,  were  almost  insurmountable  obstacles  to  the  passage  of  the 
animals.  This  camp  was  situated  behind  a  sharp  granite  knob  which 
rises  from  the  valley  like  a  sugar-loaf,  as  seen  from  below;  but  which, 
in  reality,  is  the  end  of  a  ridge  a  mile  or  two  in  length.  This  is  sev¬ 
eral  hundred  feet  high  and  its  summit  is  quite  inaccessible.  Its  sides 
show  undoubted  evidence  that  it  was  once  surrounded  by  a  great  gla¬ 
cier  flowing  down  the  valley.  The  slopes  directed  towards  the  moving 
ice  are  worn  and  polished,  and  huge  boulders  have  been  pushed  up  on 
them,  and  left  all  along,  wherever  the  angle  was  not  too  steep  for  frag¬ 
ments  of  rock  to  lie.  The  meadow  occupies  a  basin  behind  this  knob, 
which  appears  to  have  been  scooped  out  by  a  glacier. 

From  the  Sugar  Loaf  Rock  there  is  a  magnificent  view  up  the  .valley 


OEOL.  VOL.  I. — 48 


378 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


to  the  group  of  mountains  forming  the  western  crest  of  the  Sierra,  the 
culminating  point  of  which  was  named  Mount  Brewer.  This  was 
directly  east,  and  about  ten  miles  distant.  A  grand  view  was  also  had 
of  the  great  moraine  on  the  eastern  side  of  the  extreme  south  fork  of 


King’s  River ;  this  moraine  stretches  along  for  six  or  eight  miles  in  an 
unbroken  line,  resembling  an  immense  artificial  embankment,  as  will 
be  noticed  farther  on. 

In  moving  from  Camp  170  to  171,  the  party  crossed  King’s  River,  a 
stream  twenty  feet  broad,  and  travelled  up  the  valley  of  the  south 
branch  of  the  south  fork  of  that  river,  camping  at  the  western  base  of 
Mount  Brewer,  seven  miles  east-southeast,  of  Camp  170,  and  at  an  ele¬ 
vation  of  9969  feet  above  the  sea.  From  this  point  farther  progress 
with  animals  was  entirely  out  of  the  question.  The  fork  on  which 
Camp  171  was  situated  runs  from  Kaweah  Peak,  nearly  straight  north- 
northwest,  about  twenty  miles  in  distance,  to  the  main  King’s  River. 
A  ridge  which  runs  from  Mount  Brewer  to  Kaweah  Peak  forms  the 


eastern  edge  of  this  valley,  and  rises  generally  to  an  altitude  of  12,000 
feet  and  in  places  to  about  14,000.  On  the  west,  the  ridge  which 
bounds  the  valley,  extending  from  Mount  Silliman  to  Kaweah  Peak,  is 
also  about  12,000  feet  high ;  while  Camp  175,  in  the  valley,  nine  miles 
west  of  Mount  Brewer,  was  found  to  be  6300  feet  below  the  summit  of 
that  peak.  These  figures  will  give  an  idea  of  the  tremendously  rough 
character  of  the  country,  especially  if  considered  in  connection  with  the 
circumstance  that  these  slopes,  a  mile  high,  are  cut  by  numerous  side- 
canons,  with  almost  vertical  walls. 

At  the  head  of  this  valley  a  great  glacier  formerly  originated,  and 
extended  down  between  its  walls,  far  towards  the  great  plain  of  Cali¬ 
fornia.  On  the  eastern  side  of  the  valley  a  medial  moraine  still  exists 
in  all  its  perfection  of  form,  as  if  just  left  by  the  glacier,  and  it  is  the 
most  extensive  and  striking  one  which  has  been  observed  by  us  in  the 
State.  It  was  formed  between  the  main  glacier  and  a  smaller  side  one 
which  originated  just  north  of  Mount  Brewer.  Its  appearance  is  that 
of  a  vast  embankment  of  loose  boulders  and  angular  fragments  of  rock, 
piled  up  with  the  steepest  slope  on  which  such  materials  will  lie  with¬ 
out  sliding,  the  upper  edge  of  the  western  side  being  elevated  from 
1400  to  1500  feet  above  the  bottom  of  the  valley.  On  the  side  nearest 


THE  HEAD  OF  KERN  AND  KING’S  RIVERS. 


379 

to  the  mountain  the  depression  is  much  less  marked,  as  may  be  seen 
from  the  annexed  wood-cut  (Fig.  56). 


Fig.  56. 

Section  of  Moraines  on  tiie  South  Fork  of  King’s  River. 


w. 


K. 


a 


a.  Slope  of  eastern  ridge,  which  rises  to  13,000  feet  above  the  sea.  b.  Valley,  500  feet  below  c. 
c.  Crest  of  principal  moraine,  d.  Shelf  or  bench,  e.  Bottom  of  the  valley,  f,  g.  Moraine  on 
west  side  of  valley,  h.  Western  slope,  rising  to  about  11,000  feet  above  the  sea. 


The  two  moraines  on  the  opposite  sides  of  the  valley  are  both  very 
distinct,  but  the  eastern  one  is  much  the  largest.  The  horizontal  dis¬ 
tance  across  from  one  to  the  other  is  about  a  mile  and  a  half.  At  a 
distance,  these  moraines,  especially  the  eastern  one,  appear  as  regular 
as  railroad  embankments,  their  crests  being  quite  smooth,  and  having 
a  uniform  and  gradual  inclination  up  the  valley.  To  ascend  or  descend 
their  sides  with  animals  was  a  task  of  the  greatest  difficulty ;  but  once 
on  the  top,  travelling  was  quite  easy.  In  the  bottom  of  the  valley  the 
granite  is  everywhere  grooved  and  beautifully  polished. 

The  view  of  the  canon,  towards  its  head,  as  seen  from  this  moraine, 
near  Camp  175,  was  sublime,  strongly  resembling  the  valley  of  the 
Yosemite  in  some  of  its  grandest  features.  It  curves  but  little,  so  that 
the  view  is  unobstructed.  Great  surfaces  and  precipices  of  naked  gran¬ 
ite  are  seen,  often  over  1000  feet  high,  but  seldom  vertical,  although 
sloping  at  a  very  high  angle;  these  surfaces  are  everywhere  in  the  val¬ 
ley  rounded  and  polished.  Side  canons  of  the  same  character,  but 
still  more  precipitous,  open  into  the  main  one. 

From  Camp  171,  Mount  Brewer  was  twice  ascended,  on  the  2d  and 
4th  of  July,  by  passing  up  the  valley  in  which  the  camp  was  situated, 
and  which  divides  at  the  base  of  the  mountain,  extending  up  to  the 
crest  of  the  ridge.  Its  sides  were  found  to  be  very  steep  up  to  above 
12,000  feet,  the  southern  one  being  an  almost  vertical  wall  of  1000  feet 
in  height.  The  granite  of  this  region  is  hard,  not  very  coarse,  and  of 


380 


GEOLOGY 


OF  THE  SIERRA  NEVADA 


a  light  ash-gray  color,  with  a  pearly  lustre  when  seen  in  great  masses. 
It  is  intersected  with  veins  of  quartz  and  also  of  feldspar,  and  with 
some  made  up  of  a  mixture  of  both  these  minerals ;  these  veins  were 


Fig.  57. 


MOUNT  BREWER. 

From  a  point  three  miles  distant.  Looking  east. 


rarely  more  than  two  or  three  feet  in  thickness.  In  general,  however, 
the  rock  is  remarkably  homogeneous  and  almost  destitute  of  accidental 
minerals,  a  little  epidote  being  the  only  one  observed  in  this  region. 

The  view  from  the  summit  of  Mount  Brewer  is  one  of  the  most 
sublime  which  it  is  possible  to  obtain,  even  in  this  sublimest  portion  of 
the  Sierra.  The  snowy  peaks,  rising  to  over  11,000  feet  in  elevation, 


THE  HEAD  OF  KERN  AND  KING’S  RIVERS. 


381 


cover  a  breadth  of  more  than  twenty-five  miles,  and  the  point  of  view 
on  the  summit  of  this  mountain  is  such,  that  the  observer  is  placed  in 


Fig.  58. 


MOUNT  BREWER. 

From  the  southwest,  at  an  elevation  of  10,800  feet. 


the  very  midst  of  this  grand  assemblage.  High  peaks,  sharp  ridges 
bristling  with  pinnacles,  rocky  amphitheatres,  and  deep  canons  consti¬ 
tute  the  main  features  of  the  scene.  The  summit  is  a  loose  and  shat¬ 
tered  mass  of  angular  pieces  of  granite,  forming  a  ridge  some  thirty 
feet  long  by  five  broad,  which  from  the  west  appears  as  a  sharp  cone. 
The  eastern  side  of  the  mountain  is  a  precipice  buttressed  by  a  thin 
ridge,  running  out.  between  two  great  vertically-walled  basins,  white 
with  snow,  which  contrasts  beautifully  with  the  vivid  blue  of  the  frozen 
lakes  3000  feet  below. 

Two  views  of  Mount  Brewer  are  here  given  (Figs.  57  and  58),  the 
first  of  which  is  from  a  sketch  by  Mr.  Gardner,  the  other  an  outline  by 
Mr.  Hoffmann.  The  one  shows  better  the  form  of  the  mountain  itself; 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


382 

the  other,  the  peculiar  surface  and  bedded  structure  of  the  bare  granite 
slopes  in  its  vicinity. 

The  barometrical  measurements  make  the  height  of  Mount  Brewer 
13,886  feet;  it  is  not,  however,  the  culminating  point  of  the  Sierra, 
but  is  on  a  spur  embraced  by  two  branches  of  King’s  River.  Ten 
miles  farther  east  another  ridge  stretches  in  an  unbroken  line  north 
and  south,  and  through  its  depressions  the  blue  ranges  of  the  desert 
are  plainly  seen.  On  this  ridge  there  are  fourteen  peaks  visible,  ten 
of  which  are  as  high  as  Mount  Brewer,  and  four  higher.  One  of  these, 
directly  opposite,  and  which  appeared  to  be  the  highest  point  but  one, 
was  called  Mount  Tyndall,  in  honor  of  this  distinguished  physicist  and 
Alpine  explorer.  The  other  high  point,  eight  miles  south  of  Mount 
Tyndall,  and,  so  far  as  known,  the  culminating  peak  of  the  Sierra,  was 
named  by  the  party  Mount  Whitney.  Farther  observations,  by  Mr. 
King,  showed  that  a  point  about  two  miles  northeast  of  Mount  Tyndall 
was  a  little  higher  than  this  mountain;  it  was  named  in  honor  of  Major 
R.  S.  Williamson,  of  the  United  States  Engineers,  so  well  known  by 
his  topographical  labors  on  the  Pacific  coast,  especially  in  connection 
with  the  United  States  railroad  surveys.  Thirty -two  miles  north- 
northwest  is  a  very  high  mountain,  called  Mount  Goddard,  in  honor  of 
a  Civil  Engineer  who  has  done  much  to  advance  our  knowledge  of  the 
geography  of  California,  and  who  is  the  author  of  “  Britton  &  Rey’s 
Map.”  A  transverse  ridge  running  obliquely  across  from  Mount 
Brewer  to  Mount  Tyndall  forms  the  divide  between  the  headwaters  of 
the  Kern  and  those  of  King’s  River.  South  of  this,  the  division  of  the 
summit  of  the  Sierra  into  two  parallel  ridges  is  very  marked,  the  Kern 
flowing  in  the  tremendous  gorge  between  them.  The  eastern  ridge 
forms  an  almost  unbroken  wall  for  a  great  distance  to  the  north,  while 
the  western  one  is  less  distinctly  marked,  being  broken  through  to 
allow  of  the  passage  of  the  headwaters  of  the  King’s  and  San  Joaquin 
Rivers.  The  highest  portion  of  the  western  ridge  is  that  extending 
between  Mount  Brewer  and  Kaweah  Peak,  twelve  miles  to  the  south. 
This  last-named  peak  was  not  reached  by  our  party,  but  its  height  was 
estimated  to  be  over  14,000  feet.  From  its  great  elevation  and  pecu¬ 
liar  position,  opposite  to  the  highest  point  of  the  Sierra,  and  the  im¬ 
mense  depth  of  the  canon  of  the  Kern  between  it  and  Mount  Whit- 


ney,  it  would  probably  command  the  grandest  view  which  could  be 
obtained  in  the  whole  range  of  the  Sierra.  Ivaweah  Peak  is  distinctly 
visible  from  Visalia,  to  one  looking  up  the  valley  of  the  Kaweali  River. 

Of  the  terrible  grandeur  of  the  region  embraced  in  this  portion  of 
the  Sierra,  it  is  hardly  possible  to  convey  any  idea.  Mr.  Gardner,  in 
his  notes  of  the  view  from  Mount  Brewer,  thus  enumerates  some  of  the 
most  striking  features  of  the  scene :  “  Canons  from  two  to  five  thous¬ 
and  feet  deep,  between  thin  ridges  topped  with  pinnacles  sharp  as 
needles ;  successions  of  great,  crater-like  amphitheatres,  with  crowning 
precipices  over  sweeping  snow-fields  and  frozen  lakes ;  everywhere 
naked  and  shattered  granite  without  a  sign  of  vegetation,  except  where 
a  few  gnarled  and  stormbeaten  pines  ( Pinas  contorta1  P.  albicaulis ,  and 
P.  Breweri *)  cling  to  the  rocks  in  the  deeper  canons ;  such  were  the 
elements  of  the  scene  we  looked  down  upon,  while  cold  gray  clouds 
were  drifting  overhead.”  Mount  Brewer  was  ascended  July  4th,  1864, 
by  Messrs.  Brewer,  Hoffmann,  and  Gardner,  and  the  American  flag 
was  duly  planted  on  its  summit,  in  honor  of  the  day. 

The  upper  part  of  the  mountain  slopes  rapidly  on  all  sides  for  2000 
feet  from  the  summit,  then  falls  off  more  gradually  on  the  west  to¬ 
wards  the  canon  of  the  south  fork  of  King’s  River.  On  the  east,  it 
breaks  off  suddenly  into  a  great  amphitheatre,  the  head  of  a  canon 
between  4000  and  5000  feet  deep  below  the  crest,  surrounded  by  sheer 
vertical  walls,  and  with  glacier-polished  slopes  at  the  bottom,  over 
which  are  scattered  several  small  and  beautiful  lakes.  These  canons  and 
precipices,  which  lie  between  the  two  principal  ridges,  constitute  the 
main  difficulty  in  reaching  and  exploring  the  eastern  summit  peaks. 
The  region  is  desolate  and  cold ;  but  these  hindrances,  incidental  to  all 
high  mountain  climbing*  could  be  overcome,  were  it  not  for  the  impas¬ 
sable  precipices  which  continually  block  the  way,  necessitating  long 
detours,  and  rendering  it  impossible  to  reach  any  high  peak  without 
a  long  series  of  perilous  and  extremely  fatiguing  ascents  and  descents. 

As  want  of  provisions  and  the  absolute  impossibility  of  proceeding 
any  farther  with  the  animals  were  sufficient  reasons  to  prevent  the 


*  The  provisional  name  of  a  new  species  of  pine,  first  noticed  by  Mr.  King  on  Mount 
Silliman,  and  which  will  be  described  in  the  volume  of  Botany. 


384 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


1 


whole  party  from  making  any  attempt  to  climb  the  summit  of  the  east¬ 
ern  ridge,  Mr.  King  volunteered  to  undertake  this  task,  although  it 
seemed  to  most  of  the  party  that  it  was  quite  impossible  to  reach  either 
of  the  highest  peaks  from  the  western  side.  Packing  provisions  for 
six  days  and  one  blanket,  he  started,  accompanied  by  Richard  Cotter, 
from  the  camp  at  the  base  of  Mount  Brewer,  July  4th,  and  the  fol¬ 
lowing  account  of  the  trip,  in  which  the  summit  of  Mount  Tyndall  was 
reached,  is  given  nearly  in  Mr.  King’s  own  words: 

“  To  follow  down  the  ridge  which  forms  the  divide  between  King’s 
and  Kern  Rivers,  and  which  runs  obliquely  across  from  Mount  Brewer 
to  Mount  Tyndall,  was  impossible,  for  it  rose  in  sharp  crags  above  us, 
and  had  we  been  able  to  pass  around  these,  we  should  have  been 
stopped  by  vertical  clefts  over  a  thousand  feet  deep.  We  began  there¬ 


fore  to  climb  down  the  eastern  slope  of  the  ridge,  instead  of  trying  to 
keep  on  its  crest.  The  only  way  down  was  along  a  sloping  shelf,  on 
which  we  were  obliged  to  proceed  with  the  greatest  caution,  as  our 
packs  had  a  constant  tendency  to  overbalance  us,  and  a  single  misstep 
would  have  been  fatal.  At  last  we  reached  the  base  of  the  cliff  safely, 
and  made  our  way  rapidly  down  a  long  snow-slope  and  over  huge 
angular  masses  of  debris  to  the  margin  of  a  frozen  lake. 

“  We  were  now  in  the  amphitheatre;  the  crags  towering  around  us 
were  all  inaccessible,  and  we  were  obliged  to  spend  six  hours  in  climb¬ 
ing  down  from  the  outlet  of  the  lake,  over  a  slope  of  smooth  granite, 
polished  by  glaciers  and  kept  constantly  wet  by  a  shallow  current  of 
water,  into  King’s  River  canon,  and  then  up  again  over  a  long,  diffi¬ 
cult  debris-slope  and  across  several  fields  of  snow,  into  another  amphi¬ 
theatre.  Of  this  the  southern  wall  is  the  divide  between  King’s  and 
Kern  Rivers.  The  sky,  by  this  time,  had  become  quite  overcast,  and 
we  were  obliged  to  take  refuge  under  some  overhanging  rocks,  while  a 
severe  hail-storm  went  by.  We  started  on  again,  hoping  to  cross  over 
to  Kern  Canon ;  but  the  ascent  proved  very  difficult,  and  night  overtook 
us  at  the  foot  of  a  cliff  2000  feet  high.  There  was  no  wood,  so  we 
burned  paper  and  dead  carices  enough  to  make  some  luke-warm  tea, 
and  finding  a  crevice  among  the  ice  and  granite  blocks,  somewhat 
sheltered  from  the  biting  winds,  we  retired.  The  elevation  was  over 
12,000  feet,  and  the  air  stinging  cold;  but  the  sunset  view  was  glori- 


THE  HEAD  OF  KERN  AND  KING’S  RIVERS. 


385 


ous.  The  east  wall  of  the  basin  was  brilliantly  lighted  up,  its  hundred 
pinnacles  were  of  pure  yellow,  relieved  by  the  dark  blue  of  the  sky, 
which  is  so  noticeable  when  one  looks  up  from  a  deep  canon  in  the 
Sierra.  A  long  slope  of  snow  opposite  us  warmed  with  a  soft  rosy 
tinge  (the  Alpine  glow),  and  the  rugged  ridge  behind  us  cast  a  ser¬ 
rated  gray  shadow  across  it,  which  slowly  crept  up  arid  scaled  the 
granite  wall,  until  only  the  very  topmost  spires  were  in  the  light.  All 
night  long,  large  masses  of  granite  came  crashing  down  from  the 
crags  overhead,  striking  at  times  too  near  for  comfort. 

“  The  next  morning  we  ate  our  frozen  venison  by  starlight,  and 
started  at  sunrise  to  ascend  the  snow  slope  before  it  should  become 
softened.  We  had  to  cut  steps,  and  after  working  up  awhile  it  became 
quite  difficult,  so  that  we  were  three  hours  in  reaching  the  rocks,  after 
which  we  climbed  two  hours  more,  until  we  came  to  a  very  bad  ravine 
where  it  was  impossible  to  proceed  with  our  packs.  It  was  now  that 
our  reata  came  into  play,  and  we  took  turns  in  climbing  the  length  of 
it,  and  pulling  packs  and  blankets  after  us,  reaching  the  top  about 
noon,  by  which  time  the  novelty  of  this  method  of  ascent  had  quite 
worn  oft*.  What  was  our  consternation  to  find  ourselves,  as  we  scaled 
the  summit,  on  the  brink  of  an  almost  Yosemite  cliff!  We  walked 
along  the  edge,  however,  for  some  distance,  until  at  last  we  discovered 
three  shelves,  each  about  fifty  feet  below  the  other,  from  the  lowest  of 
which  we  might,  by  good  luck  and  hard  climbing,  work  along  the  face 
of  the  cliff  to  a  sort  of  ravine,  down  which  we  might  probably  reach 
the  debris.  I  tied  the  reata  firmly  about  my  body,  and  Cotter  lowered 
me  down  to  the  first  shelf;  he  then  carefully  sent  down  the  precious 
barometer  and  our  packs.  Next,  he  made  a  fast  loop  in  the  lasso, 
hooked  it  over  a  point  of  rock  and  came  down  hand-over-hand,  whip¬ 
ping  the  rope  off  the  rock  to  which  it  had  been  fastened,  thus  sever¬ 
ing  our  communication  with  the  top  of  the  cliff  This  operation  was 
repeated,  not  without  considerable  danger,  from  the  impossibility  of 
finding  a  firm  rock  around  which  to  secure  the  rope,  until  the  bottom 
was  at  last  safely  reached.  At  the  foot  of  the  debris  was  a  beautiful 
lake,  half  a  mile  long,  the  Kern  River  being  visible  below  as  a  little 
brook,  which  was  once  the  bottom  of  the  bed  of  a  great  glacier. 

“  There  were  a  few  Pinas  contorta ,  visible  down  the  course  of  the 


QEOL.  VOL.  I. — 49 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


Kern,  and  quite  a  grove  of  P.  Breweri ;  these,  with  a  few  willows  and 
an  Alpine  Ribes ,  were  all  the  vegetation  we  could  see,  excepting  a  few 
carices.  Camp  was  made  at  the  base  of  the  peak,  after  climbing  up  a 
difficult  ridge,  near  a  little  cluster  of  the  Pinus  contorta ;  this  was  about 
11,000  feet  above  the  sea. 

“  The  next  day  the  summit  was  reached,  without  serious  difficulty, 
after  some  risky  climbing  of  smooth  dome-shaped  masses  of  granite, 
where  the  only  support  and  aid  in  climbing  was  an  occasional  crack. 
The  barometer  stood,  at  12  m.,  at  18,104,  the  temperature  of  the  air 
being  44°.  On  setting  the  level,  it  was  seen  at  once  that  there  were 
two  peaks  equally  high  in  sight,  and  two  still  more  elevated,  all  within 
a  distance  of  seven  miles.  Of  the  two  highest,  one  rose  close  by, 
hardly  a  mile  away;  it  is  an  inaccessible  bunch  of  needles,  and  we  gave 
it  the  name  o.f  Mount  Williamson.  The  other,  which  we  called  Mount 
Whitney,  appeared  equally  inaccessible  from  any  point  on  the  north  or 
west  side;  it  is  between  seven  and  eight  miles  distant,  in  a  south-south¬ 
east  direction,  and  I  should  think  fully  350  feet  higher  than  our  peak. 
(Farther  examination  showed  that  it  was  really  600  or  700  feet  higher 
than  Mount  Tyndall.)  Within  our  field  of  view  were  five  mountains 
over  14,000  feet,  and  about  fifty  peaks  over  13,000. 

u  The  five  highest  peaks  are  all  on  the  eastern  ridge.  Owen’s  Valley, 
a  brown  sage  plain,  lies  10,000  feet  below  on  the  one  side,  and  Kern 
Canon,  once  the  rocky  bed  of  a  grand  old  glacier,  4000  feet  down  on 
the  other.  About  fifteen  miles  north  of  here,  King’s  River  cuts  through 
the  western  ridge  and  turns  at  a  right  angle  towards  the  plain.  Korth 
of  this  point,  again,  the  two  great  ridges  unite  in  a  grand  pile  of  gran¬ 
ite  mountains,  whose  outlines  are  all  of  the  most  rugged  and  fantastic 
character.  Twenty-five  miles  south,  the  high  group  ends,  there  (cer¬ 
tainly  for  a  breadth  of  sixty  miles)  forming  one  broad,  rolling,  forest- 
covered  plateau,  8000  to  9000  feet  in  elevation, 

“  From  Mount  Brewer  to  Kaweali  Beak,  the  two  culminating  points 
of  the  western  ridge,  for  a  distance  of  fifteen  miles  there  is  nothing 
that  can  be  called  a  separate  mountain;  it  is,  rather,  a  great  mural 
ridge,  capped  by  small  sharp  cones  and  low  ragged  domes,  all  covered 
with  little  minarets.  At  one  place  the  ridge  forms  a  level  table;  upon 
tins  lies  an  unbroken  cover  of  snow.  To  the  eastward,  all  this  range. 

7  O 


THE  HEAD  OF  KERN  AND  KING’S  RIVERS. 


387 


from  King’s  River  gateway  to  Kaweah  Peak,  presents  a  series  of  blank, 
almost  perpendicular  precipices,  broken  every  mile  or  so  by  a  bold 
granite  buttress.  Between  these  are  vast  snow-tields,  and  also  num¬ 
berless  deep  lakes,  of  which  the  most  elevated  are  frozen. 

“  The  few  Pitius  contorta ,  and  the  groves  of  our  new  pine  have  a  pecu¬ 
liar  black  color,  or,  rather,  dark  bluish-green,  which  rather  augments 
than  relieves  the  desolate,  naked  aspect  of  things.  The  only  bits  of 
bright  color  to  break  the  solemn  monotony  of  granite  and  snow  are 
the  blue  lakes,  which  lie  everywhere  in  the  ancient  glacier-beds. 

“  Far  away  in  the  north  there  is  abroad  red  band  in  the  granite ; 
other  than  that,  all  is  gray.  Beyond  Owen’s  Valley  is  a  low  desert 
range.  The  Coso  and  Inyo  Mountains  are  in  plain  sight. 

“  To  the  eastward,  parallel  ridges,  one  beyond  another,  lie  stretched 
before  us,  rigid  and  stony.  They  have  the  same  aspect  as  the  moun¬ 
tains  near  Washoe,  the  same  brown  color,  with  red  and  yellow  shad¬ 
ings. 

“  Nearly  due  north,  fifty  or  sixty  miles  distant,  rises  a  lofty  group  of 
mountains  which  culminates  in  a  white  cone.  This  must  be  very  high, 
for  unbroken  snow  covers  fully  2000  feet  on  the  south  side  of  the  peak, 
while  even  the  highest  mountains  in  our  group  have  no  snow  except 
on  the  north  flank.  These  are  probably  the  White  Mountains.  I 
venture  14,600  feet  as  a  guess  at  the  probable  elevation  of  the  highest 
point  in  the  group. 

“  We  were  six  hours  in  returning  to  the  camp  at  the  base*  and  early 
the  next  morning  we  began  our  return  march.  We  were  obliged  to 
take  a  new  route  home,  but  made  the  whole  successfully,  reaching  the 
camp  near  Mount  Brewer  with  our  bones  and  the  barometer  whole, 
although  twice  on  the  way  back  Cotter  came  within  a  hair’s  breadth 
of  losing  his  life,  and  once  I  almost  gave  myself  up-.” 

The  elevation  of  Mount  Tyndall,  as  calculated  from  Mr.  King’s 
observations,  compared  with  those  of  the  other  party,  and  with  the 
station  barometer  at  Camp  Babbitt*  was  fixed  at  14,386  feet;  this  is 
only  fifty-four  feet  less  than  the  altitude  of  Mount  Shasta. 

The  White  Mountains,  of  which  Mr.  King  speaks,  in  the  extract 
cited  above,  lie  just  on  the  borders  of  California  and  Nevada,  in  about 
longitude  118°,  latitude  37°  30';  they  were  distinctly  visible  to  us  from 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


388 


Mount  Dana  and  the  other  high  peaks  near  Mono  Lake.  It  is  doubt¬ 
ful  whether  the  highest  points  are  within  the  State  of  California;  but 
they  are  probably  very  near  the  line  on  one  side  or  the  other.  As  it  is 
by  no  means  impossible,  although  we  do  not  consider  it  probable,  that 
some  points  of  this  range  of  mountains  are  higher  than  any  yet  mea¬ 
sured  or  ascended  by  our  parties,  we  still  have  to  remain  for  some 
time  in  uncertainty  as  to  whether  California  can  claim  the  highest  ele¬ 
vations  in  the  country  as  within  her  borders;  we  can,  at  least,  say  that 
the  highest  measured  ones  are. 

After  Mr.  King’s  return  to  Camp  171,  at  the  eastern  base  of  Mount 
Brewer,  the  whole  party  went  back  to  Big  Meadows,  having  been  out 
of  provisions  for  several  days,  with  the  exception  of  a  few  strips  of 
jerked  bear  meat.  Here,  also,  they  were  to  meet  the  escort  which 
was  considered  indispensable  for  safely  exploring  the  region  to  the 
north.  Mr.  King,  however,  not  being  satisfied  with  his  first  attempt 
to  reach  the  culminating  point  of  the  Sierra,  made  another  start  from 
Visalia  July  14th,  with  no  other  company  than  an  escort  of  two 
soldiers.  Ilis  intention  was  to  follow  the  Owen’s  Lake  and  Visalia 
trail,  which  leads  up  the  Kaweah  River,  keeping  the  south  fork  from 
its  junction  with  the  main  river.  It  was  supposed  that  it  might  be 
possible  to  reach  the  summit  of  Mount  Whitney  from  this  side,  previ¬ 
ous  explorations  having  shown  that  this  could  not  be  accomplished 
from  the  northwest  or  west. 

The  first  range  of  foot-hills  on  the  line  of  the  Kaweah  is  of  a  highly 
m etam orphic  rock  cut  by  east  and  west  quartz  veins.  This  formation 
continues  only  two  or  three  miles,  and  is  succeeded  by  granite,  which 
continues  through  the  whole  range.  The  Kaweah  emerges  from  the 
mountains  through  a  narrow  cut  or  gateway,  and  above  this  it  occupies 
for  some  distance  a  winding  valley  with  considerable  bottom-land, 
sometimes  as  much  as  a  mile  wide  on  both  sides.  The  stream  mean¬ 
ders  between  chaparral-covered  ridges  which  are  deeply  furrowed  by 
precipitous  canons.  About  twenty  miles  from  the  plain  a  narrow  belt 
of  limestone  was  traversed ;  it  was  highly  metamorphosed,  of  a  gray 
color,  and  destitute  of  fossils.  It  was  remarkable  as  being  entirely 
included  in  the  granite. 

The  first  camp  was  at  forty  miles  distance  from  the  edge  of  the  foot- 


THE  HEAD  OF  KERN  AND  KING’S  RIVERS. 


389 


lulls,  the  road  up  the  valley  being  intensely  hot,  dry,  and  dusty.  From 
this  camp  the  trail  led  over  a  rolling  plateau  of  high  altitude  (probably 
between  8000  and  9000  feet),  partly  covered  by  forests  of  Pinus  con- 
torta ,  and  partly  by  chains  of  meadows.  North  of  the  road  was  a  range 
of  bald,  granite  hills,  with  groves  of  pine  scattered  about  their  bases, 
an  occasional  patch  of  snow  appearing  on  the  higher  points.  This 
chain  of  peaks  seems  to  be  the  continuation  of  the  divide  between  the 
south  and  main  Kaweah  Rivers,  and  it  continues  eastward  to  the  sum¬ 
mit  of  the  Sierra,  being  the  southern  termination  of  the  high  ranges 
to  the  north ;  south  of  it  the  country  falls  oil*  gradually  to  Walker’s 
Pass,  forming  numerous  broad,  flat-topped  ridges,  which  give  the 
region  the  general  aspect  of  a  table-land,  scored  down  from  north  to 
south  by  parallel  canons,  of  which  the  Kern  occupies  the  deepest.  The 
main  and  north  forks  of  this  river  rise  far  to  the  north  of  this  table- 
land,  and  cut  their  way  through  it,  while  the  south  fork  heads  on 
its  southern  slope,  and  joins  the  main  river,  about  eight  miles  below 
where  the  trail  crosses.  This  plateau  is  entirely  of  granite,  and  the 
vegetation  varies  according  to  the  altitude.  West  of  the  canon  of  the 
south  fork,  the  forests  are  chiefly  of  the  Pinus  coniorta ;  between  this 
and  the  main  Kern  are  line  groves  of  P.  Jeffreyi ,  and  occasional  oaks. 
The  mountains  of  the  ridge  between  the  main  and  south  forks  of  the 
Kaweah  are  all  of  granite ;  those  at  the  western  end  are  of  very  light- 
colored  rock ;  but  near  the  head  of  the  south  fork  the  granite  becomes 
quite  red,  and  the  points  near  the  main  summit  vary  from  dark-brown 
to  yellowish-red.  The  same  change  of  color  in  the  rock  is  observed  in 
going  from  the  Yosemite  to  Mount  Lyell.  In  the  valley  of  the  South 
Kern,  the  granite  is  much  altered,  probably  from  the  decomposition  of 
pyrites,  as  a  good  deal  of  oxide  of  iron  was  seen  around  the  springs 
issuing  from  it.  In  the  region  between  this  and  the  main  Kern,  there 
are  large  accumulations  of  granitic  detritus  on  the  surface.  Where  the 
trail  crosses  the  main  Kern,  the  river  is  twenty-five  or  thirty  yards 
wide ;  the  water  is  clear  and  cold,  and  abundantly  supplied  with  trout. 

From  this  point  the  old  trail  bent  southward,  crossing  the  mountains 
some  distance  below  Little  Owen’s  Lake;  the  new  one  was  built  no 
farther,  and  from  here  it  was  necessary  to  continue  the  exploration, 
without  any  other  guides  than  the  eye  and  the  compass.  Striking  the 


890 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


north  fork  of  the  Kern,  at  that  point  only  a  brook  four  or  five  yards 
wide,  Mr.  King  followed  it  up  for  several  miles,  to  where  it  breaks 
through  an  east  and  west  range  of  craggy  peaks,  which  comes  down 
like  an  immense  spur,  at  right-angles  to  the  general  course  of  the 
Sierra,  and  is  continued  as  an  elevated  ridge  far  down  the  north  side 
of  the  Kaweah.  This  range  heads  in  a  very  high  and  bare  granitic 
peak,  called  Sheep  lfock,  from  the  great  number  of  mountain  sheep 
found  in  this  vicinity.  It  is  about  eight  miles  south  of  Mount  Whit¬ 
ney,  and  is  the  termination  of  this  high  portion  of  the  Sierra. 

Korth  of  this  spur,  or  lateral  range,  through  which  the  north  and 
main  forks  of  the  Kern  both  make  their  way,  there  is  a  quadrilateral 
area,  comprised  between  the  two  great  divisions  of  the  Sierra  on  the 
east  and  west  sides,  and  having  on  the  north  the  transverse  ridge 
which  connects  Mount  Tyndall  with  Mount  Whitney.  In  this  the  main 
Kern  heads  with  many  branches,  and  to  the  east  of  it,  in  the  midst 
of  every  difficulty,  Mr.  King  worked  for  three  days  before  he  could 
reach  the  base  of  the  mountain,  whose  summit  he  was  endeavoring  to 
attain.  All  his  efforts,  however,  proved  unsuccessful,  as  far  as  this 
particular  object  was  concerned;  but  he  was  enabled  to  determine  the 
main  features  of  the  topography  of  a  considerable  area,  which  other¬ 
wise  would  necessarily  have  been  left  an  entire  blank  upon  our  map. 

The  highest  point  reached  by  Mr.  King  in  his  efforts  to  scale  the 
summit  of  Mount  Whitney  was,  according  to  the  most  reliable  calcu¬ 
lations,  14,740  feet  above  the  sea-level.  At  the  place  where  this  obser¬ 
vation  was  taken,  he  was,  as  near  as  he  was  able  to  estimate,  between  * 
800  and  400  feet  lower  than  the  culminating  point  of  the  mountain, 
which  must  therefore  somewhat  exceed  15,000  feet  in  height.  So  far 
as  known  it  is  the  highest  point  in  the  United  States,  and  the  elevation 
attained  by  Mr.  King  was  greater  than  any  other  person  has  reached, 
within  our  territories,  or  anywhere  on  the  continent  north  of  Popocat- 
apetl. 

Mount  Whitney  is  a  ridge  having  somewhat  the  outline  of  a  helmet, 
the  perpendicular  face  being  turned  towards  the  east.  There  is  snow 
on  its  summit,  which  indicates  that  there  must  be  a  flat  surface  there. 
The  mountain  is  the  culminating  point  of  an  immense  pile  of  granite, 
which  is  cut  almost  to  the  centre  by  numerous  steep  and  often  almost 


THE  HEAD  OF  THE  SAN  JOAQUIN  RIVER. 


39  I 


vertical  canons,  ending  in  high  walled  amphitheatres.  Southward  of 
the  main  peak,  there  is  a  range  of  sharp  needles,  four  of  which  are 
over  14,000  feet  high.  The  general  aspect  of  the  group  is  much  like 
that  of  Mount  Tyndall.  This  mountain  has  been  approached  on  all 
sides,  except  from  the  east,  and  found  to  be  utterly  inaccessible.  Mr. 
King  thinks  it  possible,  however,  that  some  route  may  yet  be  found  by 
which  the  summit  can  be  reached. 


Section  III. — The  Head  of  the  San  Joaquin  River. 


During  the  time  while  Mr.  King  was  exploring  about  the  sources  of 
Kern  River,  Professor  Brewer  and  party  continued  their  route  north¬ 
ward,  in  the  hope  of  being  able  to  cross  over  the  higher  ridges  of  the 
Sierra  to  the  head  of  the  San  Joaquin.  They  left  the  Big  Meadows 
July  17th,  and  made  their  way  into  the  great  canon  of  the  south  fork 
of  King’s  River  by  a  terribly  steep  road,  the  descent  being  between 
4500  and  5000  feet.  The  canon  here  is  very  much  like  the  Yosemite. 
It  is  a  valley,  from  half  a  mile  to  a  mile  wide  at  the  bottom,  about 
eleven  miles  long  and  closed  at  the  lower  end  by  a  deep  and  inaccessi¬ 
ble  ravine  like  that  below  the  Yosemite,  but  deeper  and  more  precipi¬ 
tous.  It  expands  above  and  branches  at  its  head,  and  is  everywhere 
surrounded  and  walled  in  by  grand  precipices,  broken  here  and  there 
by  side  canons,  resembling  the  Yosemite  in  its  main  features.  The 
walls  of  the  King’s  River  canon,  however,  are  nowhere  vertical  to  so 
great  a  height  as  Tutucanula ;  but  rather  resemble  the  Sentinel  and 
Cathedral  Rocks,  or  the  Three  Brothers,  of  the  Yosemite  Valley. 
They  rise  at.  various  points  to  heights  estimated  to  be  from  3500  to 
6000  feet  above  their  base,  and  there  is  but  little  debris  at  the  foot  of 
the  walls.  The  height  of  the  lower  end  of  the  valley  (Camp  178) 
above  the  sea  was  found  to  be  approximately  4737  feet;  that  of  the 
upper  end  (Camp  179)  5218  feet.  At  the  head  of  the  valley,  occupying 
a  position  analogous  to  that  of  the  Half  Dome  at  the  Yosemite,  is  the 
most  elevated  part  of  the  wall ;  it  is  nearly  vertical,  and  between  6500 
and  7000  feet  high. 

The  King’s  River  canon  rivals  and  even  surpasses  the  Yosemite  in 


392 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


% 


the  altitude  of  its  surrounding  cliffs;  but  it  lias  no  features  so  striking 
as  the  Half  Dome,  or  Tutucanula,  nor  has  it  the  stupendous  waterfalls 
which  make  that  valley  quite  unrivalled  in  beauty ;  its  streams  descend 
by  a  series  of  what  may  be  called  (in  California)  cascades,  of  from  150 
to  200  feet  high. 

The  bottom  of  the  valley  is  covered  with  granitic  sand,  forming  a 
soil  which  supports  a  fine  growth  of  timber,  with  here  and  there  a 
meadow.  The  river  abounds  in  trout. 

The  party  came  into  the  valley  by  an  old  Indian  foot-trail,  which 
passed  out  by  the  north  fork,  over  an  exceedingly  rough  country,  and 
must  cross  the  Sierra  at  an  elevation  of  at  least  13,000  feet.  This  trail 
was  entirely  impracticable  for  animals.  As  it  was  quite  impossible  to 
get  north  at  the  head  of  the  valley,  the  party  returned  a  distance  of 
two  or  three  miles,  and  made  their  way  out  on  the  north  side,  by 
an  exceedingly  steep  and  difficult  route,  camping  four  or  five  miles 
from  the  edge  of  the  canon,  and  at  an  elevation  of  more  than  4000 
feet  above  it,  or  9308  feet  above  the  sea.  This  camp  (No.  180)  was 
situated  between  the  two  main  forks  of  King’s  River,  and  from  it  a 
series  of  fruitless  attempts  were  made  to  reach  Mount  Goddard,  about 
twenty-four  miles  distant,  in  a  nortli-northwesterly  direction.  The 
ridge  between  the  forks  of  the  King’s  rises  up  in  a  crest,  which,  three 
miles  southwest  of  Camp  180,  is  12,400  feet  above  the  sea.  From  the 
summit  of  this  ridge  there  is  a  precipitous  descent  to  the  north,  into 
the  canon  of  the  middle  fork,  which  is  perhaps  even  deeper  than  the 
one  just  described. 

The  crest  presents  a  very  serrated  outline.  Two  peaks  lying  just  in 
front  of  it  are  especially  fine;  they  are  between  five  and  six  miles  east 
of  Camp  180;  both  are  probably  over  14,000  feet  high,  the  northern 
being  a  little  the  highest.  This  we  named  Mount  King,  and  the  south¬ 
ern  one  Mount  Gardner.  Mount  King  breaks  off*  in  grand  precipices 
on  the  northwest  side,  like  the  Half  Dome ;  these  are  several  thousand 
feet  in  height,  and  almost  vertical,  producing  the  effect  of  an  immense 
obelisk.  The  annexed  wood-cut  (Fig.  59)  from  a  sketch  by  Mr.  Hoff¬ 
mann,  gives  an  idea  of  the  form  of  this  grand  peak;  the  point  of  view 
was  at  Camp  180,  about  six  miles  west  of  the  summit. 

The  region  around  the  crest  of  the  ridge  between  the  forks  of  the 


THE  HEAD  OF  THE  SAN  JOAQUIN  RIVER.  393 

Ki  ng’s  consists  of  granite  masses,  with  spurs  projecting  out  from  them, 
and  embracing  basins  of  bare  rock,  each  having  a  small  lake  at  the 
bottom.  The  only  living  things  visible  in  these  valleys  are  the  grasses 


Fig.  59. 


MOUNT  KING. 
Looking  east,  from  Camp  180. 


in  the  small  meadows  which  border  the  lakes.  Everywhere  else  are  to 
be  seen  only  smooth,  bare  rocks,  or  granitic  debris  in  steeply-sloping 
piles  at  the  base  of  the  precipices.  The  crests  of  the  ridges  are  thin 
and  shattered — so  thin  that,  in  some  cases,  they  could  only  lie  traversed 
by  hitching  the  body  over  while  sitting  astride  of  them. 

At  the  head  of  the  north  fork,  along  the  main  crest  of  the  Sierra,  is 
a  range  of  peaks,  from  13,500  to  14,000  feet  high,  which  we  called 
“  the  Palisades.”  These  were  unlike  the  rest  of  the  crest  in  outline 
and  color,  and  were  doubtless  volcanic;  they  were  very  grand  and  fan¬ 
tastic  in  shape,  like  the  rocks  seen  on  the  Silver  Mountain  trail  near 
Ebbett’s  Pass.  All  doubts  as  to  the  nature  of  these  peaks  were  re¬ 
moved  after  observing  on  the  east  side  of  the  crest,  in  Owen’s  Valley, 


GEOL.  VOL.  I. — 50 


394 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


that  vast  streams  of  lava  had  flowed  down  the  slope  of  the  Sierra,  just 
below  the  Palisades. 

Three  days  were  spent  by  the  party  in  trying  to  find  some  place 
where  the  ridge  between  the  forks  of  the  King’s  could  he  crossed  with 
animals,  so  that  the  party  could  reach  the  middle  fork  and  thence  make 
their  way  to  Mount  Goddard.  This  was  ascertained  to  he  impossible, 
and  it  was  found  necessary  to  return  to  the  canon  of  the  south  fork. 
From  here  it  was,  after  some  hesitation,  decided  to  cross  the  moun¬ 
tains  into  Owen’s  Valley,  and  after  following  it  up  for  forty  or  fifty 
miles  to  turn  west  and  cross  the  Sierra  again,  so  as  thus  to  reach  the 
headwaters  of  the  San  Joaquin,  over  a  trail  which  wTas  made,  in  1863, 
by  a  party  of  soldiers  in  pursuit  of  Indians. 

A  day  and  a  half  was  required  to  make  the  distance  of  twelve  miles 
which  lay  between  Camp  179,  in  the  south  fork  canon,  and  the  summit 
of  the  Sierra;  although  the  labor  of  crossing  was  much  facilitated  by 
the  fact  that  a  party  of  prospecters  had  crossed  here  not  long  before, 
and  had  done  a  good  deal  towards  making  a  passable  trail.  Camp 
181,  midway  between  the  valley  and  the  summit,  was  found  to  be  9627 
feet  high.  To  the  north  of  this  camp,  and  nearly  east  of  Mount  King, 
but  on  the  main  crest  of  the  Sierra,  was  a  high,  naked  rock,  rising 
fully  3000  feet  above  the  trail  at  its  base,  and  one  of  the  grandest 
objects  seen  among  these  mountains.  The  sketch  (Fig.  60)  will  serve 
to  convey  a  faint  idea  of  its  majestic  form. 

The  distance  from  Camp  181  to  the  summit  was  found  to  be  about 
eight  miles.  The  crest,  on  the  pass,  is  double,  the  first  summit  being 
11,031  feet  high,  and  the  eastern  one  12,057  feet.  The  latter  is  a  very 
sharp  ridge,  with  both  sides  inclined  at  as  steep  an  angle  as  the  loose 
materials  could  maintain  without  sliding ;  the  actual  crest  is  a  sharp 
comb  of  rock.  The  peaks  on  each  side  are  very  steep,  and  were  esti¬ 
mated  to  be  2500  feet  above  the  pass,  or  fully  14,500  feet  above  the  sea. 
At  this  time  (July  27)  there  was  no  snow  on  the  line  our  party  tra¬ 
versed,  although  large  patches  were  seen  much  lower  down  in  shaded 
localities. 

The  granite  along  the  crest  is  reddened  by  oxide  of  iron,  and  showed 
considerable  tendency  to  decomposition,  a  condition  of  things  which 


THE  HEAD  OF  THE  SAN  JOAQUIN  RIVER. 


395 


seems  to  be  peculiar  to  the  main  ridge  along  the  whole  range  from 
Mount  Whitney  north,  but  not  noticed  as  extending  far  to  the  west. 


Fig.  60. 


PEAK  NEAR  CAMP  181. 


From  the  crest  of  the  Sierra  to  its  base  in  Owen’s  Valley  is  about 
eight  miles  in  a  direct  line,  and  the  average  descent  is  just  1000  feet 
per  mile  for  that  distance.  From  the  foot  of  the  mountains,  a  gradual 
and  uniform  slope  extends  into  the  valley,  forming  an  inclined  plane, 
strewn  with  boulders  resting  upon  a  sandy  soil.  This  plain  is  dry  and 
barren,  and  covered  with  the  usual  desert  shrubs,  Artemisia,  Purshia, 
Linosyris,  and  others.  The  highest  peaks  of  the  main  crest  are  not 
more  than  ten  or  eleven  miles  from  the  valley,  and  fully  10,500  feet 
above  it.  For  a  description  of  Owen’s  Valley  and  the  route  of  the 
party  through  it,  the  reader  is  referred  to  the  chapter  devoted  to  the 
eastern  slope  of  the  Sierra. 

The  mountains  were  entered  again  at  the  head  of  the  west  branch  of 
Owen’s  Iiiver,  on  which  Camp  187  was  situated,  at  an  elevation  of 
9298  feet  above  the  sea.  To  the  north  of  this  is  an  extremely  barren 
table  of  lava,  and  on  the  south  granite.  The  valley  of  the  stream  is 


396 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


half  a  mile  wide  and  flanked  on  both  sides  by  beautifully  regular 
moraines,  from  1000  to  1200  feet  above  the  bottom. 

The  summit  of  the  Sierra  was  crossed  at  an  altitude  of  12,400  feet, 
and  although  the  crest  rose  up  in  front,  appearing  as  one  continuous 
wall  and  seemingly  not  to  be  scaled,  yet  the  ascent  was  found  to  be  on 
a  comparatively  easy  grade,  with  the  exception  of  one  rocky  place 
near  the  summit.  There  is  an  obscure  Indian  foot-trail  which  crosses 
here,  and  a  body  of  seventy  cavalry,  with  their  pack-train,  crossed  by 
it  in  June,  1863.  At  that  time  there  were  patches  of  snow  half  a  mile 
long  upon  the  road.  A  wagon-road  could  be  made  over  this  pass, 
without  much  difficulty ;  but  its  great  height,  and  the  immense  body  of 
snow  which  must  lie  here  during  nearly  or  quite  all  the  year,  forbid  the 
idea  of  any  such  undertaking.  The  crest  here  is  very  rugged,  rising 
in  precipitous  ridges  about  1000  feet  above  the  pass  in  its  immediate 
vicinity,  and  perhaps  2000  feet  at  a  little  distance  north  and  south. 

The  views  from  the  high  points  above  the  trail  at  the  summit  were 
of  the  grandest  description.  Eight  miles  to  the  north  was  a  group  of 
dark,  crimson-colored  peaks,  and  twenty-five  miles  farther  in  that 
direction  were  the  snow-clad  ranges  near  Mono  Lake.  In  a  southerly 
direction  rose  a  vast  mass  of  granite  peaks  and  ridges,  with  the  same 
sharp  scattered  crests,  vertical  cliffs  overhanging  snow-fields  and  amphi¬ 
theatres  with  frozen  lakes,  which  were  the  main  features  of  the  views 
in  the  region  about  the  head  of  King’s  River. 

On  the  west  side  of  the  pass,  there  was  one  mile  of  rocky  and  steep 
descent;  but  otherwise  no  difficulty  was  experienced.  Great  slopes 
were  traversed,  which  were  worn  and  polished  by  glaciers,  and,  as 
everywhere  else  in  the  Sierra,  these  exhibitions  of  ancient  glacial  phe¬ 
nomena  were  exhibited  on  a  much  grander  scale  on  the  west  slope  of 
the  Sierra  than  they  had  been  observed  to  be  on  the  eastern  side. 

Camp  188,  a  little  below  the  summit,  was  at  an  elevation  of  9940 
feet,  and  from  this  high  peaks  on  both  sides  were  ascended  and  exam¬ 
ined.  Mr.  Gardner  visited  the  crimson-colored  group  noticed  above, 
and  which  was  about  five  miles  north  of  the  camp.  The  rocks  were 
found  to  be  of  metamorphic  slate,  having  a  strike  of  K.  50°  W.  (mag¬ 
netic),  and  dipping  to  the  northeast,  at  an  angle  of  74°.  This  slate 
does  not  continue  for  more  than  eight  miles  to  the  north,  and  is  there 


THE  HEAD  OF  THE  SAN  JOAQUIN  RIVER. 


397 


lost  under  the  granite.  Inclosed  in  the  slate,  and  having  the  same  dip 
and  strike,  is  a  vein  sixty  to  seventy  feet  wide,  of  white  quartz-rock. 
The  “  Slate  Teaks,”  as  they  were  called,  were  found  to  he  about  13,400 
feet  in  elevation.  This  group  forms  the  northern  termination  of  the 
great  elevated  range  of  the  Sierra,  which  stretches  to  the  south,  for  a 
distance  of  over  ninety  miles,  without  any  depression  below  12,000 
feet,  in  all  probability  the  highest  continuous  mass  of  mountains  in 
North  America.  To  the  north,  between  the  Slate  Peaks  and  the  Mono 
Group,  a  considerable  depression  exists,  over  which  is  a  pass,  of  the 
height  of  which  we  have  no  positive  knowledge. 

The  point  three  miles  south  of  Camp  188,  which  was  ascended  by 
Professor  Brewer,  was  found  to  be  12,740  feet  high,  and  another  one, 
three  miles  farther  southeast,  was  about  800  feet  higher  than  this. 
These  summits  are  of  granite.  Another  patch  of  slate  was  seen,  how¬ 
ever,  in  passing  down  the  San  Joaquin  River  from  Camp  188  to  Camp 
189 ;  these  form  rather  prominent  knobs,  one  of  which  was  called  Mount 
Gabb.  Whether  the  slate  extends  south,  so  as  to  connect  with  the 
mass  of  Mount  Goddard,  was  not  ascertained.  Several  dykes  of  vol¬ 
canic  rock  were  observed  cutting  the  granite,  in  this  vicinity. 

There  is  a  great  depression  where  the  three  largest  branches  of  the 
King’s  come  together.  In  this  Camp  189  was  made,  at  a  distance  of 
twenty-two  miles  from  the  summit  of  the  Sierra,  and  6930  feet  above 
the  sea.  Grassy  meadows  occur  here,  and  rising  above  them  are  many 
rocky  knolls  rounded  by  former  glaciers.  Here  and  there  are  patches 
of  lava,  one  of  which,  near  the  camp,  was  about  a  mile  long;  it  rests 
on  the  granite,  and  is  entirely  surrounded  by  that  rock.  This  locality 
has  long  been  a  favorite  resort  of  the  Indians,  on  account  of  its  remote¬ 
ness  from  the  settled  part  of  California,  and  its  consequent  security. 
The  abundance  of  game  and  the  great  number  of  pine  trees  in  this 
valley  also  added  to  its  charms.  Thousands  of  trees  were  seen  which 
had  trenches  dug  around  them,  to  catch  the  worms  which  live  in  the 
bark,  as  is  said ;  these,  as  well  as  the  nuts  of  the  pine,  are  staple  arti¬ 
cles  of  food  among  the  “Diggers.”  All  the  movements  of  our  party 
were  watched  by  the  Indians  from  a  distance  and  signalled  by  smokes, 
but  no  attack  Avas  made,  as  there  probably  would  have  been  had  they 
not  been  provided  with  an  escort. 


398 


GEOLOGY  OE  THE  SIERRA  NEVADA. 


From  Camp  189,  the  country  to  the  south  was  explored,  in  the  direc¬ 
tion  of  Mount  Goddard,  an  important  topographical  station  for  con¬ 
necting  with  the  work  on  the  other  side  of  the  King’s.  In  going  from 
Camp  189  to  190,  the  middle  and  south  forks  of  the  San  Joaquin  were 
crossed,  and  a  due  south  course  was  kept  towards  a  high  point  on  the 
ridge,  eight  miles  distant.  The  valley  widens  out  here,  and  includes  a 
broad  belt  of  rolling  country,  with  numerous  low  hills  of  granite, 
whose  tops  and  sides  are  all  smoothly  rounded  by  glacial  action.  The 
predominant  trees  here  are  Pinas  Jeffreyi  and  P.  contorta.  As  we  rise 
out  of  the  valley,  immense  moraines  are  seen  at  the  height  of  from 
1500  to  2000  feet  above  the  valley.  A  glacier,  at  least  1500  feet  deep, 
eight  or  nine  miles  wide,  and  probably  thirty  miles  long,  perhaps  much 
more,  once  flowed  down  this  valley,  and  has  left  its  traces  everywhere 
along  its  sides. 

A  peak  a  little  south  of  Camp  190,  and  10,711  feet  above  the  sea, 
was  climbed ;  from  this  a  grand  view  of  the  Sierra  between  the  Obe¬ 
lisk  range  and  the  Mount  Brewer  group  was  obtained.  The  snow  lay 
on  this  ridge  several  hundred  feet  below  the  summit ;  but  the  Pinus 
albicaulis  grows  to  the  very  top.  This  forms  one  of  a  series  of  high 
points  which  extend  in  a  line  nearly  parallel  with  the  crest  of  the 
Sierra,  and  from  sixteen  to  twenty  miles  distant  from  it,  thus  preserv¬ 
ing  all  through  this  region  the  same  double-crested  character  which  the 
range  has  farther  south  around  the  head  of  King’s  Kiver. 

About  nine  miles  south  was  a  prominent  point  of  a  dark  color,  which 
was  presumed  to  be  volcanic,  and  it  was  thought  probable  that  it  might 
be  connected  with  the  lava  stream  which  is  seen  at  Fort  Miller.  Some 
of  the  party,  however,  who  passed  over  the  line  of  this  supposed  con¬ 
nection,  on  their  way  to  Fort  Miller,  saw  nothing  but  granite  until 
they  were  near  the  fort. 

The  next  move  took  the  party  about  twelve  miles  in  a  southeasterly 
direction,  and  to  a  point  only  eighteen  miles  from  Mount  Goddard. 
This  camp  (No.  191)  was  at  an  elevation  of  10,268  feet.  The  route 
followed  lay  along  and  over  a  ridge,  with  a  very  sharp  crest  breaking 
ofl*  in  grand  precipices  on  each  side.  It  has  also  a  parapet  along  the 
south  edge  similar  to  that  described  as  forming  the  rim  of  the  Kettle ; 
this  is  in  places  thirty  feet  high,  and  rises  like  a  grand  wall,  with  a 


THE  HEAD  OF  THE  SAN  JOAQUIN  RIVER. 


399 


narrow  shelf  on  the  north ;  from  this  there  is  a  very  steep  slope  down 
for  a  thousand  feet  or  more. 

From  Camp  191  an  unsuccessful  attempt  was  made  to  reach  Mount 
Goddard,  without  the  animals,  as  they  could  he  taken  no  farther.  The 
only  possible  way  led  along  the  divide  between  King’s  and  San  Joaquin 
Rivers,  over  a  series  of  ridges,  high  and  sharp,  with  valleys  between, 
a  thousand  feet  deep  or  more,  so  that  progress  was  excessively  slow 
and  tiresome.  Cotter  and  one  of  the  soldiers  succeeded,  after  a  day’s 
climbing,  in  getting  within  300  feet  of  the  summit,  and  hung  up  the 
barometer  just  before  it  was  too  dark  to  see  to  read  it.  They  were 
then  at  an  elevation  of  13,648  feet,  making  the  height  of  the  mountain 
about  14,000  feet.  The  return  to  an  impromptu  camp,  at  an  elevation 
of  about  12,000  feet  and  without  provisions  or  fire,  made  by  the 
remainder  of  the  party  at  the  base  of  the  mountain,  required  the  whole 
night  and  was  hazardous  in  the  extreme.  This  was  Camp  No.  192,  or 
“  Cold  Camp.” 

The  geological  structure  of  the  mountain  and  the  adjacent  ridges  is 
peculiarly  interesting  and  would  repay  a  careful  study ;  but  the  party, 
being  entirely  out  of  provisions,  was  obliged  to  beat  a  hasty  retreat. 
There  is  much  metamorphic  rock  here,  especially  mica-slate,  forming 
vein-like  masses  inclosed  in  the  granite.  Cotter  described  the  sum¬ 
mit  of  Mount  Goddard  as  made  up  of  alternate  veins  or  beds  of  slate 
and  granite.  Visible  for  miles  across  a  canon  from  Camp  192  was  a 
cl  iff  several  hundred  feet  high,  in  which  the  veined  or  bedded  structure 
of  the  granite  was  very  conspicuous,  the  dark  masses  of  the  slate  con¬ 
trasting  finely  with  the  lighter-colored  granite.  Where  the  slates  were 
seen  in  large  bodies  they  were  generally  dipping  at.  a  high  angle  to  the 
northeast,  but  sometimes  vertical  and  often  much  contorted. 

Mount  Goddard  seems  to  be  the  southern  end  of  the  belt  of  slates 
which  forms  Castle  Peak,  Mount  Dana,  and  the  high  mountains  near 
Camp  188,  as  already  noticed.  No  slate  was  seen  to  the  south  of 
Mount  Goddard  in  this  direction,  for  nearly  a  hundred  miles,  which  is 
the  distance  from  this  metamorphic  region  to  that  on  Kern  River,  near 
Keysville,  It  is  possible,  however,  that  farther  explorations  might 
show  a  connection  of  the  metamorphic  masses  through  on  this  line. 

From  Camp  191  the  party  returned  to  189,  and  from  there  worked 


400 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


• 

to  the  northwest  in  the  canon  of  the  north  fork  of  the  San  Joaquin. 
For  three-fourths  of  the  way,  the  route  followed  led  down  the  depres¬ 
sion  at  the  junction  of  the  three  forks  before  noticed.  This  depres¬ 
sion  lias  the  appearance  of  a  valley,  only  when  seen  from  the  heights 
around  it.  There  are  numerous  flats  lying  between  rounded  hills  of 
bare  granite ;  these  flats  are  sometimes  covered  by  forests,  but  many 
of  them  form  beautiful  open  meadows  in  which  many  thousand  cattle 
might  be  pastured. 

Several  small  patches  of  volcanic  rock  were  noticed  in  this  region, 
usually  a  hard,  dark-colored,  basaltic  material.  Occasionally,  however, 
the  lava  was  red  and  porous,  and  a  piece  of  pumice  was  seen  floating 
on  the  river. 


Fig.  G 1. 


CANON  OF  THE  NORTH  FORK  OF  THE  SAN  JOAQUIN. 


The  north  fork  of  the  San  Joaquin  comes  down  through  a  very  deep 
canon,  and  the  wide,  open,  valley-like  depression  terminates  here. 
This  canon  is  from  3000  to  4000  feet  deep,  and  proved  to  be  a  serious 
obstacle  to  the  advance  of  the  party.  Near  the  junction  of  the  north 
and  main  forks,  it  is  a  mere  notch,  and  its  walls  exhibit  some  grandly 
picturesque  features.  The  above  wood-cut  (Fig.  61)  represents  one 


T11E  HEAD  OF  THE  SAN  JOAQUIN  RIYER. 


401 


of  bare  and  rugged  masses  of  rock,  rising  1500  feet  above  the  inaccessi¬ 
ble  gorge  at  its  base,  through  which  hows  the  north  fork. 

Two  or  three  miles  southeast  of  this  is  a  most  remarkable  dome, 
more  perfect  in  its  form  than  any  before  seen  in  the  State.  It  rises  to 
the  height  of  1800  feet  above  the  river,  and  presents  exactly  the  appear¬ 
ance  of  the  upper  part  of  a  sphere;  or,  as  Professor  Brewer  says,  “  of 
the  top  of  a  gigantic  balloon  struggling  to  get  up  through  the  rock.” 

Camp  194,  in  the  canon,  was  at  an  altitude  of  about  4750  feet,  while 
the  ranges  to  the  east  and  northeast  rose  from  4000  to  5000  feet  above 
this,  and  those  on  the  west  about  3000  feet.  The  sides  of  the  canon 
are  very  abrupt,  and  present  immense  surfaces  of  naked  granite,  re¬ 
sembling  the  valley  of  the  Yosemite.  There  are  everywhere  in  this 
valley  the  traces  of  former  glaciers,  on  an  immense  scale,  and  as  the 
party  rose  above  the  canon  on  the  north,  in  leaving  the  river,  the  mo¬ 
raine  on  the  opposite  side  was  seen  very  distinctly,  and  appeared  to  be 
at  an  elevation  of  not  less  than  3000  feet  above  the  bottom  of  the  valley. 
It  was  evident  that  the  glaciers  which  came  down  the  various  branches 
of  the  San  Joaquin  all  united  here  to  form  one  immense  “  sea  of  ice,” 
which  filled  the  whole  of  the  wide  depression  spoken  of  above,  and  left 
its  moraines  at  this  high  elevation  above  the  present  river-bed. 

The  party  passed  out  of  the  canon  to  the  northwest,  first  ascendinga 
steep  ridge,  over  3000  feet  high,  and  then  entering  a  wide  elevated  val¬ 
ley,  where  Camp  195  was  made,  at  an  elevation  of  about  7250  feet.  On 
the  high  ridge,  traversed  in  getting  to  this  camp,  were  many  boulders 
of  lava,  which  must  have  been  brought  from  some  more  northerly  point 
and  dropped  in  their  present  position  by  ancient  glaciers.  The  source 
of  these  boulders  seems  to  have  been  near  Mount  Clark,  in  the  Obelisk 
Range.  The  view  from  the  summit  of  the  ridge  was  a  grand  one, 
commanding  the  whole  of  the  Mount  Lyell  and  Obelisk  groups,  as  well 
as  the  main  range  of  the  Sierra  to  the  east,  where  are  many  dark- 
colored  peaks,  apparently  volcanic.  A  very  high  and  massive  peak  was 
seen  to  the  east  of  Mount  Lyell,  which  it  nearly  equalled  in  altitude; 
it  was  called  Mammoth  Mountain,  and  was  estimated  to  be  13,000  feet 
in  height. 

In  the  depression  to  the  west  of  the  ridge  noticed  above  are  heavy 
forests  and  fine  meadows  scattered  over  the  country,  into  which  many 


UEOL.  VOL.  I. — 51 


402 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


cattle  had  been  driven  from  Fresno  County,  to  escape  the  extreme 
drouth  of  the  season.  The  meadows  occupy  the  flats  or  level  intervals 
between  the  domes  of  granite;  grassy-flats,  as  they  are  called,  occur 
everywhere  along  the  Sierra  at  about  this  altitude,  on  the  high  lands 
between  the  large  streams. 

In  the  region  about  Camp  195  a  few  narrow  belts  of  mica-slate  were 
noticed  in  the  granite ;  some  patches  of  lava  were  also  observed. 

Camp  196,  a  few  miles  north  of  195,  was  at  the  base  of  a  prominent 
peak,  which  was  supposed  to  belong  to  the  Obelisk  group,  for  which 
the  party  was  aiming.  On  ascending  it,  however,  it  was  found  to  be 
about  eight  miles  due  south  of  the  Obelisk.  It  was  found  to  he  10,950 
feet  high  and  commanded  a  fine  view.  The  base  is  of  granite,  and 
it  is  capped  with  lava ;  from  this  point  it  was  noticed  that  some  of  the 
peaks  of  the  Obelisk  group  are  covered  with  the  volcanic  rock  in  the 
.  same  way. 

Eighteen  miles  northeast  of  this  is  the  lowest  gap  or  pass  over  the 
Sierra  which  occurs  between  Carson’s  and  Walker’s  Passes,  a  distance 
of  about  250  miles.  An  approximation  to  its  height  was  obtained  by 
an  observation  of  the  barometer  on  the  peak  ascended  near  Camp  195, 
at  a  point  which  was  ascertained  by  levelling  to  be  at  about  the  same 
altitude  as  the  pass  itself.  The  result  of  the  calculation  gave  9200  feet 
as  the  height  of  the  summit  of  the  pass,  which  is  considerably  lower 
than  the  Mono  Pass.  Cattle  have  been  driven  across  to  Owen’s  Valley 
over  this  route,  the  north  fork  of  the  San  Joaquin  being  crossed  at  a 
point  much  farther  up  than  where  our  party  traversed  it,  and  where 
the  canon  is  not  nearly  so  deep. 

From  Camp  196  the  party  made  their  way,  as  rapidly  as  the  worn- 
out  condition  of  the  men  and  horses  permitted,  to  Clark’s  ranch,  on  the 
trail  from  Mariposa  to  the  Yosemite,  They  first  travelled  in  a  south¬ 
westerly  direction,  over  a  region  of  dome-shaped  granite  hills,  for  a 
distance  of  twenty- three  miles,  and  camped  at  the  head  of  the  Chiquito 
San  Joaquin,  and  at  the  altitude  of  7463  feet.  Many  meadows  were 
passed,  into  which  large  numbers  of  cattle  had  been  driven.  One  of 
these  is  known  as  Yeal’s  ranch,  or  Jackass  Meadows.  From  this  point 
there  were  trails  which  could  be  followed,  and  this  was  the  first  sign 
ot  a  return  to  the  regions  of  civilization. 


THE  HEAD  OF  THE  MERCED  AND  TUOLUMNE  RIVERS.  403 


Gold  had  been  found  during  the  summer  in  the  bed  of  the  Chiquito 
Joaquin,  and  also  on  the  Lower  King’s  River,  and  quite  a  number  of 
miners  had  flocked  to  this  region.  Of  the  productiveness  of  the  dig¬ 
gings  our  party  had  no  means  of  judging,  nor  was  the  precise  locality 
known;  as  near  as  could  be  ascertained,  it  was  about  ten  miles  from 
Camp  197. 

Camp  198  was  at  the  head  of  the  Fresno  River,  and  at  an  elevation 
of  3217  feet.  Along  this  part  of  the  route  the  rock  was  chiefly  meta- 
morphic,  but  highly  crystalline,  and  exceedingly  obscure  in  its  lithologi¬ 
cal  characters.  It  forms  a  red  soil  in  decomposing,  and  is  probably  the 
source  of  the  gold  found  in  this  vicinity.  The  trail  descended  suffi¬ 
ciently  to  strike  the  true  foot-hill  vegetation ;  but  afterwards  rose  again 
into  the  High  Sierra,  and  on  the  23d  of  August,  Camp  199  was  made 
at  Clark’s  Ranch,  at  an  elevation  of  4270  feet,  by  the  party,  who  were, 
by  this  time,  pretty  nearly  at  the  end  of  their  resources,  as  well  as  their 
strength.  One  of  them,  indeed,  remained  in  a  precarious  condition  for 
some  weeks,  and  did  not  entirely  recover  until  after  the  lapse  of  seve¬ 
ral  months. 

Section  IV. — The  Region  about  the  Heads  of  the  Merced  and 

Tuolumne  Rivers. 

That  portion  of  the  High  Sierra  in  which  head  the  numerous  branches 
of  the  Merced  and  Tuolumne  Rivers  is,  on  many  accounts,  one  of  the 
most  attractive  regions  of  the  State  to  the  lovers  of  the  picturesque. 
Although  its  scenery  may  not  exhibit  that  awful  sublimity  of  desola¬ 
tion  which  marks  the  Sierra  at  the  heads  of  King’s  and  Kern  Rivers, 
yet  it  has  some  peculiar  features  which  are  to  be  found  nowhere  else 
in  the  State.  It  has  by  far  the  greatest  water-falls,  not  only  of  the 
Sierra  Nevada,  but,  as  may  fairly  be  claimed,  of  the  world,  for  we 
know  of  nothing  of  this  kind  which  will  compare  with  the  falls  of  the 
Merced  or  of  the  Yosemite  Creek  in  height  or  sublimity,  or  in  the 
general  effect  of  their  surroundings.  The  region  of  this  grand  scenery 
in  Mariposa  County  is  comparatively  accessible,  so  much  more  so  in¬ 
deed  than  that  described  in  the  two  preceding  sections,  that  thousands 
will  visit  the  Yosemite  to  one  who  scales  the  summit  of  Mount  Brewer 


404 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


or  Kaweali  Peak.  But  the  traveller,  desirous  of  learning  something  of 
the  grandeur  of  the  mountain  scenery  of  the  Pacific  side  of  our  conti¬ 
nent,  should  not  he  contented  with  seeing  the  Yosemite  only ;  he  should 
push  on  still  farther  into  the  heart  of  the  Sierra,  visit  the  sources  of  the 
Tuolumne  River,  and  climb  Mount  Dana;  all  of  which  may  be  done, 
even  by  ladies,  without  danger  and  almost  without  difficulty.  It  is 
true  that,  at  present,  there  are  no  accommodations  for  pleasure-travel¬ 
lers  in  this  region,  and  they  must,  therefore,  provide  themselves  with 
camp-equipage  and  provisions;  but,  as  the  tide  of  travel  turns  more 
strongly  every  year  in  this  direction,  the  time  must  soon  come  when  a 
public  house  at  Soda  Springs,  in  the  Tuolumne  Valley,  will  afford  the 
necessary  facilities  for  visitors  to  this  region,  and  the  ascent  of  Mount 
Dana,  or  other  yet  undescribed  peaks,  will  be  as  common  as  a  visit  to 
the  White  Mountains  and  the  summit  of  Mount  Washington  was  a  few 
years  ago. 

In  the  hope  of  directing  the  attention  of  travellers  and  tourists  to  this 
grand  and  yet  easily  accessible  portion  of  the  Sierra  Nevada,  we  shall, 
in  this  section,  dwell  rather  more  on  the  scenery  and  topography  of 
the  region  than  we  should  otherwise  feel  authorized  to  do  in  a  volume 
devoted  to  geology.  In  that  part  of  the  final  report  which  will  be  de¬ 
voted  to  Physical  Geography,  we  hope  to  be  able  to  go  much  more  at 
length  into  all  the  subjects  which  will  especially  interest  the  intelligent 
traveller  in  the  Sierra,  and  the  consideration  of  which  will,  as  we  hope, 
induce  others  to  continue  the  observation  of  the  physical  phenomena  of 
this  great  chain  of  mountains — a  task  which  we  can  only  begin,  and 
must  then  leave  for  others  to  work  upon,  knowing  that  the  material  is 
ample  and  interesting  enough  to  give  full  scope  to  the  powers  of  many 
a  lover  of  science,  nature,  or  art,  who  may  come  after  us,  and  perhaps 
owe  his  happiest  and  best  inspirations  to  the  study  of  these  glorious 
obj  ects. 

The  exploration  of  the  region  about  the  heads  of  the  Merced  and 
Tuolumne  Rivers  was  chiefly  done  by  our  whole  party  in  the  months 
of  J  une  and  J uly,  1863,  about  three  weeks  having  been  then  devoted  to 
the  survey  of  the  route  between  Big  Oak  Flat  and  Mono  Lake,  one  of 
which  was  spent  in  and  about  the  Yosemite  Valley.  The  next  year 
after,  however,  Professor  Brewer,  at  the  close  of  the  reconnaissance  de- 


THE  HEAD  OF  THE  MERCED  AND  TUOLUMNE  RIVERS.  405 


scribed  in  the  preceding  section,  made  a  short  visit  to  the  Yosemite. 
Still  later  in  that  season,  during  the  months  of  October  and  November, 
Messrs.  King  and  Gardner  spent  several  weeks  there,  engaged  in 
making  a  survey  of  the  valley,  for  the  use  of  the  Commissioners  ap¬ 
pointed  by  the  Governor  to  have  the  care  and  oversight  of  the  tract 
granted  by  the  United  States  to  the  State  of  California,  embracing  the 
Yosemite  Valley  and  the  Mariposa  grove  of  Big  Trees.  After  com¬ 
pleting  the  survey  of  the  grant,  Mr.  King  wrote  out  his  notes  of  the 
geological  observations  made  by  him  while  thus  engaged,  and  has 
kindly  placed  them  at  the  disposition  of  the  Survey.  An  accident  hav¬ 
ing  occurred  which  prevented  the  immediate  comparison  of  the  baro¬ 
meters  at  the  time  of  the  completion  of  the  work,  and  the  record  of  a 
subsequent  one  not  having  been  received,  the  results  of  Messrs.  King 
and  Gardner’s  observations  of  heights  may  hereafter  require  a  slight 
correction ;  but  a  sufficient  number  were  made  by  our  party,  in  1863,  to 
give  a  general  idea  of  the  elevations  around  the  valley.  To  go  into  the 
minute  details  of  the  topography  of  this  region  would  almost  require 
a  volume  by  itself.  The  map  drawn  by  Mr.  Gardner  is  now  nearly 
completed,  and  it  is  supposed  that  it  will  be  published,  either  by  the 
Commissioners  or  by  the  Geological  Survey,  according  as  the  Legisla¬ 
ture  may  determine.  A  rough  survey  and  map  of  the  valley  was, 
however,  made  in  1863  by  Mr.  Hoffmann,  which  was  intended  to  be 
used  in  a  future  volume  of  our  Report,  in  clfse  we  should  not  have  the 
means  of  preparing  a  more  detailed  and  accurate  one. 

After  our  hasty  survey  of  the  Yosemite  Valley,  in  1863,  we  followed 
the  trail  from  there  to  Mono  Lake,  camping  for  about  two  weeks  near 
the  head  of  the  Tuolumne  River,  and  securing  the  first  outline  of  the 
geography  of  that  extensive  region,  which  had  never  been  laid  down 
with  even  approximate  accuracy  on  any  published  map  ;  indeed,  so  far 
as  we  can  Learn,  the  higher  elevations  of  this  part  of  the  Sierra  had 
never  been  ascended,  certainly  not  measured  or  located,  previous  to 
our  visit.  Since  that  time,  however,  we  learn  that  Mount  Dana  has 
been  visited  repeatedly,  and  that  our  pioneer  work  in  this  region  has 
already  had  the  effect  to  attract  quite  a  number  of  visitors  in  its 
direction. 

In  a  previous  cliapter  we  briefly  noticed  the  geology  of  the  route  to 


406 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


the  Yosemite,  as  far  as  the  Bower  Cave  (see  page  235),  the  point  where 
the  trails  from  Big  Oak  Flat  and  Coulterville  unite.  That  by  the  last- 
named  place  is  the  one  usually  followed,  and  the  distance  to  the  valley 
is  called  fifty  miles ;  this  portion  of  the  route  must  be  done  on  horse 
or  mule-back.  Two  days  are  required  to  make  the  distance  comforta¬ 
bly,  and  the  journey  cannot  fail  to  be  a  delightful  one  to  those  who  are 
accustomed  to  riding,  and  not  alarmed  at  mountain  trails,  where  with  a 
reasonable  amount  of  care  there  is  no  danger  whatever.  The  trail 
passes,  for  the  entire  distance,  through  the  magnificent  and  unrivalled 
forests  of  the  Sierra,  and  the  sight  of  these  alone  would  well  repay  the 
cost  of  the  excursion. 

From  Bower  Cave,  we  cross  obliquely  over  the  great  limestone  belt, 
already  described,  in  a  southeasterly  direction,  to  Bull  Creek,  the  dis¬ 
tance  being  called  six  miles;  here  we  have  attained  an  altitude  of  2793 
feet.  Beyond  this,  the  auriferous  slates  are  struck  again,  and  there  are 
some  washings  in  Bull  Creek,  and  along  a  branch  of  it  which  the  trail 
follows  for  some  distance  in  a  northerly  direction.  A  little  beyond 
this  the  granite  is  met  with,  and  this  is  the  only  rock  seen  along  the 
road,  until  we  have  passed  far  beyond  the  Yosemite  and  reached  the 
very  summit  of  the  Sierra.  Along  the  edge  of  the  granite,  however, 
there  are  limited  patches  of  highly  metamorphosed  strata,  apparently 
masses  of  the  slates  which  have  been  caught  up  in  the  intrusive  rock, 
and  have  had  their  origirfal  structure  so  nearly  obliterated  that  it  is  quite 
difficult  to  make  out  their  real  nature.  A  few  miles  after  passing  the 
western  edge  of  the  granitic  formation,  the  rock  becomes  very  homo¬ 
geneous,  and  appears  to  contain  exceedingly  few  accidental  minerals, 
although  there  are,  in  places,  a  considerable  number  of  quartz  veins ; 
these,  however,  become  less  and  less  frequent  as  we  ascend  towards 
the  crest  of  the  mountains. 

From  Bull  Creek  to  Black’s  Ranch  is  called  six  miles,  and  parties 
often  spend  the  night  here  on  their  way  to  or  from  the  valley.  Six 
miles  farther  on  is  Deer  Flat,  where  was,  in  1863,  the  last  house  on  the 
road  before  reaching  the  Yosemite.  From  here  to  Crane  Flat  is  twelve 
miles,  and  the  trail  between  the  two  places  passes  over  and  along  a 
high  granitic  spur  of  the  Sierra,  rising  at  the  summit  to  the  elevation 
of  6669  feet.  Along  this  part  of  the  route  many  quartz  veins  were 


THE  HEAD  OF  THE  MERCED  AND  TUOLUMNE  RIVERS.  407 


noticed.  At  Crane  Flat,  6130  feet  above  the  sea,  there  was,  in  1863, 
a  deserted  shanty,  and  abundant  forage  for  animals.  The  forests  in 
the  vicinity  are  superb,  consisting  of  pine,  spruce,  and  fir,  with  a  small 
group  of  the  Big  Trees  not  far  from  the  Flat.  This  “  Flat,”  as  these 
small  level  areas  of  grassy  land  in  the  high  mountains  are  usually 
called,  is  hut  a  few  acres  in  extent,  and  is  almost  wet  enough  to  he 
called  a  marsh. 

From  here  on  to  the  Yosemite,  the  character  of  the  scenery  begins 
to  undergo  a  change,  and  to  show  indications  of  an  approach  to  the 
higher  regions  of  the  Sierra.  The  larger  outcrops  of  granite  assume 
more  and  more  of  the  dome  form,  and  are  almost  hare  of  vegetation. 
The  forests  become  less  dense ;  the  sugar  pine,  that  most  striking  of 
all  the  trees  of  California  (the  Big  Trees  themselves  hardly  excepted), 
grows  less  frequent,  and  the  firs  and  spruce  begin  to  predominate  over 
the  pines. 

From  Crane  Flat  to  the  edge  of  the  valley,  where  it  is  met  by  the 
trail  on  the  north  side,  is  called  ten  miles,  making  fifty-two  miles  from 
Coulterville.  At  a  little  distance  from  the  trail  on  the  southern  or 
right-hand  side,  is  a  place  from  which  a  partial  view  of  the  Yosemite 
Valley  may  be  obtained.  It  is  not  a  satisfactory  one,  however,  on 
account  of  the  number  of  trees  in  the  way  and  the  bend  in  the  valley 
itself,  which  cuts  off  the  view  of  all  the  upper  part.  In  this  respect  it 
is  inferior  to  the  bird’s-eye  view  of  the  Yosemite  and  all  its  surround¬ 
ings  which  is  had  from  “  Inspiration  Point,”  on  the  Mariposa  trail  into 
the  valley,  and  approaching  it  from  the  south.  Those  who  desire  to 
have  the  finest  and  most  comprehensive  view  of  the  whole  scene  at 
the  first,  should  enter  the  valley  by  the  Mariposa  and  return  by  the 
Coulterville  trail;  those,  on  the  other  hand,  who  would  reserve  to  the 
last  the  grandest  effect  of  all,  and  who  would  wait  until  they  have 
become  familiar  with  the  details,  before  having  the  whole  scene  spread 
out  before  them,  will  do  well  to  reverse  the  order  of  their  coming  and 
ffoinff. 

O  © 

The  Yosemite  Valley  is  situated  on  the  Merced  River.  It  is  about 
140  miles  in  a  direction  a  little  south  of  east  from  San  Francisco.  It 
is  nearly  in  the  centre  of  the  State,  north  and  south,  and  exactly  mid- 


408 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


way  between  the  east  and  west  bases  of  the  Sierra,  here  about  seventy 
miles  wide. 

The  valley  is  a  nearly  level  area,  about  eight  miles  in  length  and 
varying  from  half  a  mile  to  a  mile  in  width.  For  the  lower  six  miles 
its  course  is  from  northeast  to  southwest;  the  upper  two  miles  are 
nearly  at  right-angles  to  this,  the  angle  of  the  bend  being  at  the  spot 
where  the  Yosemite  Fall  comes  over  the  precipice  on  the  north  side. 
Below  the  expanded  portion  of  the  valley,  the  Merced  enters  a  terribly 

deep  and  narrow  canon,  which  is  said  to  be  inaccessible,  and  which  we 

% 

had  no  time  to  explore. 

To  make  the  peculiar  features  of  the  Yosemite  more  intelligible  to 
those  who  have  not  seen  it,  or  who  have  not  enjoyed,  what  is  next  best 
to  the  thing  itself,  the  admirable  photographs  of  Mr.  C.  E.  Watkins,* 
we  give  a  wood-cut  (Fig.  62),  representing  a  portion  of  both  sides 
of  the  valley,  and  which  is  one  of  the  first  near  views  which  the  trav¬ 
eller  gets  of  the  grander  masses,  whether  he  descends  by  the  Coulter- 
ville  or  the  Mariposa  trail.  On  the  right-hand  or  south  side  (the  view 
being  taken  looking  up,  or  to  the  northeast),  we  have  the  cliffs  on  the 
face  of  which  the  Bridal  Veil  Fall  is  seen.  Behind  this  is  a  much 
higher  mass,  which  forms  a  portion  of  the  Cathedral  Bock.  On  the 
other  side  is  Tutucanula,  or  El  Capitan,  the  first  of  these  names  being 
the  original  Indian  appellation  for  this  mighty  cliff,  and  supposed  to  be 
either  the  name  of  some  great  chief,  or  else  the  word  by  which  their 
“  Great  Spirit”  or  Deity  was  called,  while  “El  Capitan”  is  the  term 
by  which  the  first  visitors  to  the  valley  undertook  to  translate  the  abo¬ 
riginal  idea  into  the  Spanish. 

As  the  idea  of  the  dimensions  and  vertically  of  the  walls  of  the 
Yosemite  may  be  somewhat  less  easily  taken  from  the  shaded  wood- 
cut,  a  section  (Fig.  63)  is  appended  of  the  valley  at  this  point,  on  an 

*  These  photographs,  thirty  in  number,  and  twenty-one  inches  by  sixteen  in  size,  are 
pronounced  by  all  artists  to  be  as  near  perfection  as  possible.  They  are  already  well 
known  and  widely  distributed  through  the  Eastern  States,  and  will  be  more  so.  The 
glass  stereographs  taken  in  the  valley,  by  Mr.  Watkins,  are  in  some  respects  even  more 
effective  than  the  photographs.  All  the  views  of  the  Yosemite  given  in  this  volume  are 
taken  from  these  photographs,  by  permission. 


TIIE  HEAD  OF  THE  MERCED  AND  TUOLUMNE  RIVERS.  409 

equal  scale  of  vertical  and  horizontal  distances,  from  careful  measure¬ 
ments  by  Mr.  King.  The  distance  across  from  the  inside  edge  of  the 


El  Capitau. 


Bridal  Veil  Fall. 


YOSEMITE  VALLEY. 


talus  on  one  side  to  that  on  the  other  (represented  in  the  section  by 
the  dark  shading)  is  a  little  less  than  half  a  mile. 


Fig.  63. 


El  Capital). 


Bridal  Veil. 


SECTION  ACROSS  THE  YOSEMITE. 


GEOL.  VOL.  I. — 52 


410 


GEOLOGY  OF  TIIE  SIERRA  NEVADA. 


From  these  two  wood-cuts  it  will  be  evident  to  all  that  the  peculiar 
features  of  the  Yosemite  are;  first,  the  near  approach  to  vertically  of 
its  walls;  next,  their  great  height,  not  only  absolutely,  hut  as  com¬ 
pared  with  the  width  of  the  valley  itself;  and,  finally,  the  very  small 
amount  of  debris,  or  talus,  at  the  bottom  of  these  gigantic  cliffs.  These 
are  the  great  characteristics  of  the  valley  throughout  its  whole  length  ; 
but  besides  these,  there  are  many  other  striking  peculiarities,  and  feat¬ 
ures  both  of  sublimity  and  beauty  which  can  hardly  be  surpassed,  if 
equalled,  by  those  of  any  mountain  scenery  in  the  world. 

Tutucanula  is  an  almost  vertical  cliff  of  naked,  smooth  granite. 
From  its  edge  down  to  the  valley  below  is  about  3300  feet,  according 
to  Mr.  King’s  measurement ;  it  is  usually  called  3600  feet,  which  may 
be  the  extreme  height  of  its  slightly  rounded  summit.  It  is  undoubt¬ 
edly  one  of  the  grandest  objects  in  the  Yosemite,  and  it  would  be  diffi¬ 
cult  to  find  anywhere  in  the  world  a  mass  of  rock  presenting  a  perpen¬ 
dicular  face  so  imposing  and  elevated.  The  pile  of  debris  at  its  base 
(represented  by  the  dark  shade  in  the  section)  is  so  insignificant  in 
dimensions,  compared  with  the  cliff  itself,  that  it  is  hardly  noticed  at 
all  from  some  points,  in  a  general  view  of  the  valley,  and  this  is  one  of 
the  most  striking  and  unique  features  of  the  scene,  for  it  is  a  condition 
of  things  of  the  rarest  possible  occurrence.  We  know  of  nothing  like 
it  in  any  other  part  of  the  world. 

T1  le  Bridal  Veil  Fall,  of  which  the  Indian  name  is  “  Pohono,”  is 
about  1000  feet  in  height,  and,  during  the  season  when  the  stream  is 
fed  by  the  melting  snow  on  the  mountains  above,  it  is  a  wonderfully 
beautiful  object.  The  body  of  water  is  not  large,  but  is  sufficient  to 
produce  the  most  picturesque  effect.  As  it  is  swayed  backwards  and 
forwards  by  the  varying  force  of  the  wind,  it  is  continually  altering  its 
form,  so  that  it  seems,  especially  as  seen  from  a  distance,  to  flutter  like 
a  white  veil ;  hence  the  name,  which  is  both  appropriate  and  poetical. 

Proceeding  up  the  valley,  we  find,  a  little  above  the  Bridal  Veil  Fall, 
and  on  the  same  side,  the  prominent  and  massively  sculptured  pile  to 
which  the  name  of  Cathedral  Bock  is  given  (Fig.  64).  It  was  not 
measured  by  us,  but  it  appears  to  be  about  3000  feet  in  height.  Its 
massive,  and  yet  nobly  proportioned,  form  can  be  perhaps  faintly  con¬ 
ceived  of  from  the  wood-cut,  which  reproduces  with  accuracy  the  out- 


THE  HEAD  OF  THE  MERCED  AND  TUOLUMNE  RIVERS.  411 


line,  and 
are  the 


some  of  the  artistic  effect,  of  the 
“  Cathedral  Spires,”  two  slender 


photograph.  Behind  this 
and  beautiful  columns  of 


Fig.  G4. 


CATHEDRAL  ROCK. 


granite,  on  the  same  gigantic  scale  as  everything  else  in  this  region, 
and  which  here  are  passed  almost  unnoticed,  although,  by  themselves, 
in  other  parts  of  the  world,  they  would  be  considered  objects  of  the 
greatest  interest. 

A  couple  of  miles  farther  up  the  valley,  and  on  the  other  side,  is  the 
next  cluster  of  peaks,  a  triple  row  of  summits  rising  in  steps  one 
above  the  other ;  these  are  called  the  “  Three  Brothers.”  From  the 
highest  of  these,  nearly  4000  feet  above  the  valley,  there  is,  as  Mr. 
King  thinks,  the  finest  view  which  can  be  had  of  the  Yosemite  itself 
and  the  whole  surrounding  region  up  to  the  crest  of  the  Sierra. 


412 


GEOLOGY  OF  TIIE  SIERRA  NEVADA. 


Opposite  the  Three  Brothers  is  a  prominent  point,  which  stands  ont 
near  the  amffe  where  the  valley  makes  its  most  distinct  turn,  and 
which,  from  its  fancied  likeness  to  a  gigantic  watch-tower,  is  called 
“  Sentinel  Rock.”  As  seen  from  the  southwest,  it  is  a  group  of  cliffs, 
of  which  the  outside  one  has  quite  the  form  of  an  obelisk,  very  regular 
and  beautiful,  for  at  least  a  thousand  feet  down  (see  Fig.  65).  The 
entire  height  of  the  Sentinel  above  its  base  is  a  little  over  3000  feet. 


Fig.  65. 


SENTINEL  ROCK. 


Three-quarters  of  a  mile  southeast  of  the  Sentinel  is  the  Dome  of  the 
same  name,  4150  feet  high,  and  one  of  the  most  perfect  of  the  dome¬ 
shaped  masses  of  granite  so  peculiar  to  the  Sierra  Nevada.  Its  hori¬ 
zontal  section  is  nearly  circular,  and  its  slope  very  regular  and  uniform 
on  all  sides.  From  its  summit  the  view  is,  of  course,  extremely  grand ; 


- 


PLATE  II,  p.  413. 


THE  YOSEMITi  FALL 


TIIE  HEAD  OF  THE  MERCED  AND  TUOLUMNE  RIVERS.  413 


it  is  especially  line  in  the  direction  of  the  Obelisk  Group  of  moun¬ 
tains,  and  it  commands  the  canon  of  the  south  fork  of  the  Merced — 
“  Illilouette,”  as  it  is  called  by  the  Indians.  From  this  point  the  glacial 
phenomena,  and  especially  the  regular  and  extensive  moraines,  of  that 
valley  are  finely  displayed.  The  profile  of  the  Half  Dome,  of  which 
more  farther  on,  is  best  seen  from  the  Sentinel  Dome. 

.From  nearHlie  foot  of  Sentinel  Ilock,  looking  directly  across  the 
valley,  we  have  before  us,  if  not  the  most  stupendous  feature  of  the 
Yosemite,  at  least  the  most  attractive  one,  namely  the  Yosemite  Fall. 
We  have  endeavored  to  convey  some  idea  of  the  grandeur  and  beauty 
of  this  fall,  by  reproducing  (in  Plate  2)  as  well  as  can  be  done  on  the 
small  scale  allowable  in  this  volume  and  on  wood,  one  of  Mr.  Watkins’ 
photographs ;  but  it  is  in  vain  that  we  attempt,  by  any  work  of  art,  to 
do  more  than  give  the  faintest  echo  of  the  impression  which  this  glori¬ 
ous  exhibition  of  nature  produces  on  all  who  are  so  fortunate  as  to  see 
it  under  favorable  circumstances*  About  the  time  of  full  moon,  and 
in  the  month  of  May,  June,  or  July,  according  to  the  dryness  and  for¬ 
wardness  of  the  season,  is  the  time  to  visit  the  Yosemite,  and  to  enjoy 
in  their  perfection  the  glories  of  its  numerous  water-falls.  Those  who 
go  later,  after  the  snow  has  nearly  gone  from  the  mountains,  see  the 
streams  diminished  to  mere  rivulets  and  threads  of  water;  they  feel 
satisfied  with  the  other  attractions  of  the  valley,  its  stupendous  cliffs, 
domes  and  canons*  and  think  that  the  water-falls  are  of  secondary 
importance,  and  that  they  have  lost  little  by  delaying  the  time  of  their 
visit.  This  is  not  so;  the  traveller  who  has  not  seen  the  Yosemite 
when  its  streams  are  full  of  water  has  lost,  if  not  the  greater  part,  at 
least  a  Jarge  portion,  of  the  attractions  of  the  region,  for  so  great  a 
variety  of  cascades  and  falls  as  those  which  leap  into  this  valley  from 
all  sides  has,  as  we  may  confidently  assert,  never  been  seen  elsewhere 
— both  the  Bridal  Veil  and  the  Nevada  Fall  being  unsurpassed  in 
some  respects,  while  the  Yosemite  Fall  is  beyond  anything  known  to 
exist,  whether  we  consider  its  height  or  the  stupendous  character  of 
the  surrounding  scenery. 

The  Yosemite  Fall  is  formed  by  a  creek  of  the  same  name,  which 
heads  on  the  west  side  of  the  Mount  Hoffmann  Group,  about  twenty 
miles  north  of  the  valley.  The  volume  of  water  varies,  of  course,  with 


414 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


tlie  season ;  at  the  ordinary  stage  of  summer,  through  the  months  of 
June  and  July,  it  is  about  twenty  feet  wide  and  two  feet  deep,  on  the 
average.  From  the  edge  of  the  cliff  over  which  it  is  precipitated  to 
the  bottom  of  the  valley,  the  perpendicular  distance  is,  in  round  num¬ 
bers,  2550  feet.  Professor  Brewer’s  measurement  gave  2041,  and  that 
of  Mr.  King  2537,  the  difference  being  due  to  the  circumstance  that 
the  lip  or  edge  is  a  gradual  curve,  and  so  highly  polished  that  a  near 
approach  to,  or  a  precise  definition  of,  the  place  where  the  perpendicu¬ 
lar  portion  of  the  fall  commences  is  impossible.  As  the  quantity  of 
water  was  at  a  minimum  at  the  time  of  Mr.  King’s  visit,  so  that  lie 
could  approach  with  safety  more  nearly  to  the  edge,  it  is  probable  that 
his  result  is  the  nearest  to  the  truth. 

The  fall  is  not  in  one  perpendicular  sheet.  There  is  first  a  vertical 
descent  of  1500  feet,  where  the  water  strikes  on  what  seems  to  be  a 
projecting  ledge;  but  which  in  reality  is  a  shelf  or  recess,  almost  a 
third  of  a  mile  back  from  the  front  of  the  lower  portion  of  the  cliff'. 
From  here  the  stream  finds  its  way  in  a  series  of  cascades  down  a 
descent  equal  to  626  feet  perpendicular,  and  then  gives  one  final  plunge 
of  about  400  feet  on  to  a  low  talus  of  rocks  at  the  base  of  the  precipice. 
As  these  various  falls  are  in  one  vertical  plane,  the  effect  of  the  wdiole 
from  the  other  side  of  the  valley  is  nearly  as  grand,  and  perhaps  even 
more  picturesque,  than  it  would  be  if  the  descent  was  made  in  one 
sheet  from  the  top  of  the  cliff'  to  the  bottom.  The  mass  of  water  in 
the  1500  foot  fall  is  too  great  to  allow  of  its  being  entirely  broken  up 
into  spray,  but  it  widens  very  much  as  it  descends,  and  as  the  sheet 
vibrates  backwards  and  forwards  with  the  varying  pressure  of  the 
wind,  which  acts  with  immense  force  on  this  long  column  of  water,  the 
effect  is  indescribably  grand,  especially  under  the  magical  illumination 
of  the  full  moon.  The  cliff  a  little  east  of  the  edge  of  the  Yosennte 
Fall  rises  in  a  bold  peak  to  the  height  of  3030  feet  above  the  valley; 
it  can  be  reached  through  Indian  Canon,  a  little  farther  east,  and  from 
here  a  magnificent  view  of  the  whole  region  may  be  obtained.  The 
ascent  to  the  summit  of  the  upper  fall  and  the  return  to  the  valley  may 
be  made  in  one  day,  but  only  by  good  mountain-climbers. 

About  two  miles  farther-  up  from  the  falls  just  noticed,  the  main 
valley  of  the  Yosemite  comes  to  an  end,  and  runs  out  into  three  dis- 


. 


, 


■Qit  d  in  auyvTia: 


THE  HEAD  OF  THE  MERCED  AND  TUOLUMNE  RIVERS.  415 


tinet  canons,  eacli  of  which,  however,  has  new  wonders  to  disclose. 
The  Merced  River  keeps  the  middle  one  of  these,  and  its  course  here 
is  about  the  same  that  it  was  below,  or  nearly  west.  It  holds  this 
direction  nearly  up  to  the  base  of  the  Mount  Lyell  Group,  where  it 
heads.  In  the  left-hand,  or  northwesterly  canon,  the  Tenaya  Fork 
comes  down ;  in  the  right-hand  one,  the  south  fork  or  the  Illilouette. 


Fig.  66. 


THE  II ALF  DOME.  YOSEMITE  VALLEY. 


Following  up  the  Tenaya  Fork,  which  rises  on  the  east  side  of 
Mount  Hoffmann,  we  have  on  the  right  hand,  just  at  the  entrance  of 
the  canon,  that  grandest  and  loftiest  mass  of  the  Tosemite  Valley, 
called  the  Half  Home.  This  has  been  in  sight,  however,  through  all 
the  upper  part  of  the  valley,  above  the  Vosemite  Falls,  and  is  a  con¬ 
spicuous  point  from  all  the  region  around.  Its  form,  as  seen  from 
near  the  entrance  of  the  canon,  may  he  understood  from  the  wood- 
cuts  (Fig.  66  and  Plate  3).  In  one  it  is  seen  flatwise ;  in  the  other, 


416 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


edgewise.  It  is  an  inaccessible  crest  of  granite,  rising  to  the  height 
of  4737  feet  above  the  valley,  the  face  fronting  towards  Tenaya 
Creek  being  absolutely  vertical  for  2000  feet  down  from  the  summit. 
The  outline  of  this  wonderfully  formed  mass  of  rock  may  be  seen  in 
the  annexed  section  (Fig.  67)  through  the  Half  Home,  Lake  Tisayac 


Fig.  67. 


\ 


\ 


/ 


North  Dome. 


Half  Dome. 


SECTION  THROUGH  THE  DOMES. 


and  the  North  Home,  on  an  equal  vertical  and  horizontal  scale,  the 
distance  across  from  the  summit  of  one  dome  to  the  other  being  about 
a  mile  and  three-quarters.  Such  a  representation  of  a  mountain  or 
cliff  seems  to  be  something  imaginary,  rather  than  the  plotting  of  mea¬ 
sured  angles  and  distances,  which  it  really  is.  By  turning  to  Plate  3, 
which  is  accurately  copied  from  a  photograph,  it  will  be  seen  that  there 
is  no  exaggeration  in  this  outline.  The  whole  appearance  of  the  mass 
is  that  of  an  originally  dome-shaped  elevation,  with  an  exceedingly 
steep  curve,  of  which  the  western  half  has  been  split  off*  and  has  be¬ 
come  engulfed.  Hence  the  name,  which  is  one  that  seems  to  sug¬ 
gest  itself  at  first  sight  of  this  truly  marvellous  crest  of  rock.  From 
all  the  upper  part  of  the  valley,  and  from  the  heights  about  it,  the  Half 
Home  presents  an  aspect  of  the  most  imposing  grandeur ;  it  strikes 
even  the  most  casual  observer  as  a  new  revelation  in  mountain  forms ; 
its  existence  would  be  considered  an  impossibility  if  it  were  not  there 
before  us  in  all  its  reality ;  it  is  an  unique  thing  in  mountain  scenery, 
and  nothing  even  approaching  it  can  be  found  except  in  the  Sierra 
Nevada  itself. 


THE  HEAD  OF  THE  MERCED  AND  TUOLUMNE  RIVERS.  417 


The  North  Dome,  on  the  opposite  side  of  the  valley  of  Tenaya 
Creek,  is  another  of  these  rounded  masses  of  granite,  of  which  the 
concentric  structure,  already  frequently  alluded  to  in  this  chapter,  is 
very  marked.  The  annexed  wood-cut  (Fig.  68),  engraved  by  Mr. 


Fig.  68. 


jSORTII  DOME — YOSEMITE  VALLEY. 


Andrews  from  one  of  Watkins’s  photographs,  will  illustrate  both  the 
form  of  the  dome  and  its  structure.  It  is  3568  feet  in  elevation  above 
the  valley,  and  is  very  easy  of  ascent  from  the  north  side.  At  the 
angle  of  the  canon,  appearing  as  a  buttress  of  the  North  Dome,  is  the 
Washington  Column,  a  grand,  perpendicular  mass  of  granite,  and  by 
its  side  the  Royal  Arches,  an  immense  arched  cavity  formed  in  the 
cliffs  by  the  giving  way  and  sliding  down  of  portions  of  the  rock,  the 
vaulted  appearance  of  the  upper  part  of  it  producing  a  very  fine  effect. 

Farther  up  the  canon  of  Tenaya  Creek  is  a  little  lake,  called  Tisa- 


ro 


GEOL.  VOL.  I 


418 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


vac;  it  is  surrounded  by  the  most  picturesque  cliffs,  having  the  giant 
Half  Dome  overhanging  its  eastern  side. 

The  canon  of  the  Merced,  above  the  Yosemite  Valley  proper,  rises 
very  rapidly  for  the  distance  of  about  two  miles,  when  it  attains  the 
level  of  the  surrounding  plateau.  In  this  two  miles  the  river  descends 
1980  feet,  making,  besides  innumerable  cascades,  two  grand  falls,  which 
are  among;  the  greater  attractions  of  the  Yosemite,  not  only  on  account 

O  O  '  *J 

of  their  height,  and  the  lar^e  body  of  water  in  the  river  during  the 
early  part  of  the  season,  but  also  because  of  the  stupendous  peaks  and 
cliffs  by  which  they  are  surrounded. 

The  first  fall  reached  in  ascending  the  canon  is  the  Vernal,  or  Piwyae. 
ft.  is  a  simple  perpendicular  sheet,  475  feet  in  height,  as  nearly  as  we 
could  determine,  the  blinding  spray  at  the  bottom  rendering  exact 
measurements  impossible.  A  distant  view  of  this  fall,  with  a  portion 

of  the  canon  and  the  top  of  the  Half  Dome  in  the  distance  on  the  left 

# 

hand,  and  Mount  Broderick  on  the  right,  is  given  in  Plate  3.  The 
rock  behind  the  Vernal  Fall  is  a  perfectly  square  cut  mass  of  granite, 
and  it  is  wonderful  to  see  how  little  any  eroding  effect  of  water  can  be 
traced  in  its  outline.  It  would  seem  as  if  causes  nowin  action  had 
nothing  to  do  with  the  formation  of  this  step  in  the  descent  of  the  Mer¬ 
ced  down  to  the  valley  below. 

Ascending  to  the  summit  of  the  Vernal  Fall  by  a  series  of  ladders, 
and  proceeding  a  mile  farther  up  the  river,  passing  a  series  of  rapids 
and  cascades  of  great  beauty,  we  come  to  the  last  great  fall  of  the 
Merced,  namely,  the  Nevada,  or  the  “  Yowiye,”  of  the  Indians.  The 
total  descent,  from  the  edge  of  the  Nevada  Fall  to  that  of  the  Vernal, 
is  894  feet;  of  which  639,  as  near  as  we  could  determine,  is  in  one 
perpendicular  sheet.  The  Nevada  Fall,  however,  has  a  peculiar  twist 
in  it,  near  the  summit,  caused  by  the  mass  of  water  falling  on  a  pro¬ 
jecting  ledge,  which  throws  it  off*  to  one  side,  adding  greatly  to  the 
picturesque  effect.  This  may  be  seen  in  the  wood-cut  (Fig.  69),  which 
also  gives  a  view  of  the  stupendous  mass  of  Mount  Broderick,  an 
inaccessible  peak,  rising,  as  near  as  we  could  estimate,  2000  feet  above 
its  base,  and  little  inferior  to  the  Half  Dome  in  grandeur.  (See  also 
Plate  3.)  The  Nevada  Fall  is  certainly  to  be  ranked  as  one  of  the  very 
finest  cataracts  in  the  world,  taking  into  consideration  its  height,  the 


THE  HEAD  OF  THE  MERCED  AND  TUOLUMNE  RIVERS.  419 


volume  and  purity  of  the  water,  and  the  whole  character  of  the  scenery 
which  surrounds  it,  Mount  Broderick  alone  being  an  object  of  which 


the  fame  would  be  spread  world-wide,  if  it  were  not  placed  as  it  is,  in 
the  midst  of  so  many  other  wonders  of  nature. 

There  are  also  grand  cascades  in  the  South  Fork  Canon,  the  scenery 
through  the  whole  of  which  is  little  inferior  to  that  of  the  other  por¬ 
tions  of  the  Yosemite;  but,  amid  so  many  objects  of  attraction,  few 
visitors  find  time  to  examine  this  canon,  especially  as  the  trail  by 
which  it  is  reached  is  a  rough  and  difficult  one.  Judging  from  Mr. 
Watkins’s  photographs,  the  views  from  points  along  the  slopes  of  the 
South  Fork  Canon  must  be  equal  to  almost  any  which  can  be  had  in 


the  whole  region. 

In  the  angle  formed  by  the  Merced  and  the  South  Fork  Canon,  and 
about  two  miles  south-southeast  of  Mount  Broderick,  is  the  high  point, 
called  the  “  South  Dome,”  and  also,  of  later  years,  “Mount  Starr  King.” 


420 


GEOLOGY  OE  THE  SIERRA  NEVADA. 


This  is  the  most  symmetrical  and  beautiful  of  all  the  dome-shaped 
masses  around  the  Yosemite;  but  it  is  not  visible  from  the  valley  itself. 
It  exhibits  the  concentric  structure  of  the  granite  on  a  grand  scale; 
although  its  surface  is  generally  smooth  and  unbroken.  Its  summit  is 
absol utely  inaccessible. 

II  aving  thus  briefly  noticed  some  of  the  more  prominent  objects  of 
interest  about  the  Yosemite,  we  may  add  a  few  words  in  regard  to  the 
valley  itself.  This  is  an  almost  level  area,  the  fall  from  one  end  to  the 
other  of  the  valley  proper  being  only  about  fifty  feet.  The  width  of 
the  bottom-land,  between  the  slopes  of  debris  at  the  base  of  the  cliffs,  is 
only  about  half  a  mile;  below  El  Capitan, however, it  is  nearly  twice  as 
much.  Its  smooth  surface  and  brilliant  color,  diversified  as  it  is  with 
groves  of  trees  and  carpeted  with  showy  flowers,  offer  the  most  won¬ 
derful  contrast  to  the  towering  masses  of  neutral  and  light  purple- 
tinted  rocks  by  which  it  is  surrounded.  Its  elevation  above  the  sea  is, 
according  to  our  measurements,  4060  feet.  A  much  longer  series  of 
observations  than  ours  was  taken  by  Miss  Sproat,  at  the  request  of 
Messrs.  Gardner  and  King,  while  they  were  engaged  in  their  survey  ; 
the  result  has  not  yet  been  calculated.  It  will  be  safe,  however,  to  call 
the  height  of  the  valley  4000  feet,  in  round  numbers ;  the  cliffs  and 
domes  about  it  are  from  7000  to  9000  in  altitude  above  the  sea-level. 

The  trees  are  thickly  enough  scattered  over  the  valley  to  produce  a 
fine  picturesque  effect.  They  are  not  as  lofty  as  those  of  the  forests  of 
the  Sierra  at  that  altitude  usually  are.  The  predominating  species  is 
the  pitch  pine  (P.  ponderosa),  which  grows  here  from  125  to  150  feet 
high.  Besides  this,  there  are  a  number  of  P.  Jeffreyi  and  a  few  sugar 
pines.  The  white  oak  ( Q .  lobata)  and  the  evergreen  oak  (Q.  crassipo- 
cula )  are  also  common,  and  there  are  numerous  willows,  and  a  poplar, 
called  “cottonwood,”  but  really  allied  to  the  “Balm  of  Gilead,”  of 
the  Eastern  States.  On  the  cliffs  there  are  some  cedars.  In  the  high 
region  about  the  Yosemite,  at  an  elevation  of  from  3500  to  7000  feet, 
there  is  precisely  the  same  vegetation  which  has  already  been  described 
as  existing  around  Mount  Shasta,  except  that  the  trees  are  not  quite 
as  high,  and  there  are  more  black  oaks  (§.  Sonomensis )  in  the  lower 
forests. 

All  will  recognize  in  the  Yosemite  Valley  a  peculiar  and  almost 


THE  HEAD  OF  THE  MERCED  AND  TUOLUMNE  RIVERS. 


421 


unique  type  of  scenery.  Cliffs  absolutely  vertical,  like  the  upper  por¬ 
tions  ot  the  Half  Dome  and  El  Oapitan,  and  of  such  immense  heights 
as  these,  are,  so  far  as  we  know,  to  be  seen  nowhere  else.  The  dome 
form  of  mountains  is  exhibited  on  a  grand  scale  in  other  parts  of  the 
Sierra  Nevada;  hut  there  is  no  Half  Dome,  even  among  the  stupendous 
precipices  at  the  head  of  King’s  River.  It  is  natural  to  ask,  then,  how 
these  vertical  cliffs  have  been  formed,  and  to  what  geological  causes  does 
the  Yosemite  Valley  owe  its  existence? 

Most  of  the  great  canons  and  valleys  of  California  have  resulted 
from  denudation,  as  has  been  already  repeatedly  stated  in  the  course 
of  this  volume.  The  long-continued  action  of  the  tremendous  tor¬ 
rents  of  water,  rushing  with  impetuous  velocity  down  the  slopes  of  the 
Sierra,  has  excavated  those  prodigious  gorges,  by  which  the  chain  is 
furrowed  to  the  depth  of  thousands  of  feet.  But  these  eroded  canons, 
steep  as  they  may  be,  have  not  vertical  walls;  neither  have  their  sides 
the  peculiar  angular  forms  which  the  mass  of  El  Capitan,  for  instance, 
has,  where  there  are  two  perpendicular  surfaces  of  smooth  granite 
meeting  at  right-angles,  and  each  over  3000  feet  high. 

When  Messrs.  Gardner  and  King’s  map  of  the  Yosemite  is  pub¬ 
lished,  and  farther  investigations  made  to  clear  up  some  doubtful 
points,  the  theory  of  the  formation  of  this  valley  may  be  discussed 
more  intelligibly  than  it  can  be  at  present.  It  may,  however,  be  stated, 
that  it  appears  to  us  probable  that  this  mighty  chasm  has  been  roughly 
hewn  into  its  present  form  by  the  same  kind  of  forces  which  have 
raised  the  crest  of  the  Sierra  and  moulded  the  surface  of  the  moun¬ 
tains  into  something  like  their  present  shape.  The  domes,  and  such 
masses  as  that  of  Mount  Broderick,  we  conceive  to  have  been  formed 
by  the  process  of  upheaval  itself,  for  we  can  discover  nothing  about 
them  which  looks  like  the  result  of  ordinary  denudation.  The  Half 
Dome  seems,  beyond  a  doubt,  to  have  been  split  asunder  in  the  middle, 
the  lost  half  having  gone  down  in  what  may  truly  be  said  to  have 
been  “  the  wreck  of  matter  and  the  crush  of  worlds.”  It  has  been 
objected  to  this  view,  by  some  of  the  corps,  that  the  bottom  of  the  val¬ 
ley,  in  places  where  an  engulfment  must,  according  to  this  theory, 
have  taken  place,  seems  to  be  of  solid  granite,  when  there  should  be 
an  unfathomable  chasm,  filled  now,  of  course,  with  fragments,  and  not 


422 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


occupied  by  a  solid  bed  of  rock.  To  this  it  may  be  replied,  in  the  first 
place,  that  the  masses  which  have  been  engulfed  may  have  been  of 
such  enormous  size  as  to  give  the  impression,  where  they  are  only 
imperfectly  exposed,  of  perfect  continuity  and  connection  with  the 
adjacent  cliffs.  But,  again,  this  grand  cataclysm  may  have  taken  place 
at  a  time  when  the  granitic  mass  was  still  in  a  semi-plastic  condition 
below,  although,  perhaps,  quite  consolidated  at  the  surface  and  for 
some  distance  down.  In  this  case  it  is  not  impossible,  certainly,  that 
the  pressure  from  above  may  have  united  the  yielding  material  to¬ 
gether,  so  that  all  traces  of  the  fracture  would  be  lost,  except  in  that 
portion  of  it  which  affected  the  upper  crust.  If  the  bottom  of  the 
Yosemite  did  “  drop  out,”  to  use  a  homely  but  expressive  phrase,  it 
was  not  all  done  in  one  piece,  or  with  one  movement;  there  are  evi¬ 
dences  in  the  valley  of  fractures  and  cross-fractures  at  right-angles  to 
these,  and  the  different  segments  of  the  mass  must  have  been  of  quite 
different  sizes,  and  may  have  descended  to  unequal  depths. 

In  the  course  of  the  explorations  of  Messrs.  King  and  Gardner,  they 
obtained  ample  evidence  of  the  former  existence  of  a  glacier  in  the 
Yosemite  Valley,  and  the  canons  of  all  the  streams  entering  it  are 
also  beautifully  polished  and  grooved  by  glacial  action.  It  does  not 
appear,  however,  that  the  mass  of  ice  ever  filled  the  YMsemite  to  the 
upper  edge  of  the  cliffs;  but  Mr.  King  thinks  it  must  have  been  at 
least  a  thousand  feet  thick.  He  also  traced  out  four  ridges  in  the  val¬ 
ley  which  he  considers  to  be,  without  a  doubt,  ancient  moraines.  One 
of  these  ridges  is  a  low  and  narrow  band  of  fragments  of  rock  and 
rounded  boulders,  extending  from  the  base  of  the  Half  Home  in  a 
curve  down  the  valley,  and  up  again  to  the  debris  under  the  Wash¬ 
ington  Column.  This  seems  to  be  the  terminal  moraine  of  the  Tenaya 


Creek  glacier. 

A  well-defined  medial  moraine  extends  from  the  foot  of  the  western 
end  of  the  Half  Home  out  into  the  valley,  in  a  slight  curve.  Another 
one  was  formed  between  the  glaciers  descending  from  the  canon  of 
the  Merced  and  the  south  fork,  and  remains  now  as  a  large  pile  of 
debris  extending  down  thS  valley. 

A  terminal  moraine,  according  to  Mr.  King,  extends  across  the 
Yosemite  Valley  from  the  cliffs  just  below  the  Bridal  Veil  Fall,  curv- 


T 1 1 K  HEAD  OF  T11E  MERCED  AND  TUOLUMNE  RIVERS. 


4*2:1 


ing  down  the  river  on  the  south  side  and  up  again  on  the  north  until 
it  meets  the  talus  about  a  quarter  of  a  mile  below  El  Capitan,  thus 
forming  a  complete  barrier  across  the  valley.  It  is  not  very  conspicu¬ 
ous,  rising  only  about  twenty  feet  above  the  general  level,  yet  it  seems 
to  mark  an  important  change  in  the  character  of  the  talus  at  the  foot 
of  the  elitfs  of  the  Yosemite.  Above  it  the  quantity  of  debris  accu¬ 
mulated  in  this  position  is  exceedingly  small;  indeed,  there  is  in  some 
places  actually  none  at  all,  the  lower  edge  of  the  cliff  meeting  the  floor 
of  the  valley,  with  hardly  a  fragment  of  rock  lodged  in  the  angle; 
below  the  moraine,  on  the  other  hand,  the  debris  piles  are  extensive, 
uniting  at  the  river,  and  extending  high  up  the  cliffs  on  each  side. 

Tt  seems  not  unlikely  that  this  moraine  may  have  acted  as  a  dam  to 
retain  the  water  within  the  valley,  after  the  glacier  had  retreated  to  its 
upper  end,  and  that  it  was  while  thus  occupied  by  a  lake  that  it  was 
filled  up  with  the  comminuted  materials  arising  from  the  grinding  of 
the  glaciers  above,  thus  giving  it  its  present  nearly  level  surface. 

It  is  evident,  from  the  fresh  appearance  of  large  masses  of  debris 
along  the  sides  of  the  valley  that  these  materials  are  now  accumulating 
with  considerable  rapidity ;  and  when  we  consider  how  small  the  whole 
quantity  of  talus  is,  as  compared  with  the  height  and  extent  of  the 
cliffs,  we  are  forced  to  the  conclusion  that  the  time  which  has  elapsed 
since  the  Yosemite  was  occupied  by  a  glacier  cannot  have  been  very 
long.  It  would  seem  that  there  are  strong  reasons  for  believing  that 
a  great  change  in  the  climate  of  California  may  have  taken  place  within 
the  historical  period.  We  know  that  such  a  change  has  occurred,  as 
there  is  abundant  evidence  to  prove  that  the  precipitation  of  moisture 
in  the  Sierra  Nevada  was  once  vastly  greater  than  it  now  is  ;  but  to  the 
cause  of  this  change  we  have  as  yet  no  clue.  This  subject,  however, 
will  come  up  for  a  much  fuller,  and,  it  is  hoped,  a  more  satisfactory 
discussion  than  we  have  either  the  space  or  the  data  for  at  the  present 
time. 

Having  given  the  above  brief  account  of  some  of  the  more  interesting 
features  of  the  Yosemite,  we  leave  this  wonderful  valley,  and  proceed 
to  sketch  the  geography  and  geology  of  the  higher  mountain  region 
above,  at  the  head  of  the  Merced  and  Tuolumne  Rivers. 

We  followed  the  Ooulterville  trail  out  of  the  valley,  but  turned  east 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


424 


on  arriving  at  the  summit  of  the  cliff,  taking  the  usual  route  followed 
by  mule  trains  to  the  Mono  Pass.  This  trail  is  considerably  used  in 
the  summer,  as  there  is  sufficient  forage  for  animals  at  a  number  of 
points,  and  the  meadows  not  having  been  claimed  or  fenced  in,  they 
are,  as  yet,  free  to  all.  On  the  more  travelled  routes  north  of  the  Mono 
Pass,  there  are  public  houses,  the  pasture-land  is  inclosed,  and  feed 
must  be  purchased.  In  1863,  there  was  not  a  house  or  a  settler  any¬ 
where  between  Deer  Plat,  twenty-two  miles  below  the  Yosemite,  and 
the  eastern  base  of  the  Sierra. 

After  leaving  the  valley,  we  crossed  over  high  granite  ridges  running 
north  and  south  between  the  Yosemite  and  Indian  Creeks.  From  the 
summits  of  these,  tine  views  were  obtained  of  the  Half  Dome  and  the 
other  great  precipices  about  the  head  of  the  Merced  Piver.  Higher  up 
in  the  Sierra  the  mountains  no  longer  appear  in  the  form  of  domes, 
but  rise  in  sharp  ridges  and  needles,  giving  more  of  an  Alpine  character 
to  the  scenery. 

Our  first  camp,  after  leaving  the  Yosemite,  was  at  Porcupine  Flat,  a 
little  meadow  of  carices,  8173  feet  above  the  sea.  From  here  we  made 
some  explorations  of  the  north  and  south  range,  which  stretches  from 
the  North  Dome  to  the  Tuolumne  River,  a  distance  of  about  eighteen 
miles ;  it  is  the  group  of  mountains  in  which  head  the  Yosemite,  Indian 
and  Tenaya  Creeks.  The  highest  point  of  this  range,  which  we  called 
Mount  Hoffmann,  was  found  to  be  10,872  feet  in  elevation.  It  is  en¬ 
tirely  of  granite,  having  a  gentle  slope  on  the  southern  side,  but  break¬ 
ing  off  in  grand  precipices  to  the  north.  From  its  summit  the  view 
of  the  Sierra,  in  all  directions,  is  one  of  the  finest  which  can  he  obtained, 
and  its  ascent  may  be  strongly  recommended  to  those  who  have  not 
time  to  visit  the  still  higher  peaks  of  the  main  ridge  of  the  Sierra. 
The  excursion  from  the  Yosemite  to  the  summit  of  Mount  Hoffmann 
and  the  return  may  he  easily  made  in  three  days,  and  the  tourist  who 
devotes  this  amount  of  time  to  getting;  a  much  better  idea  of  the  gran- 
deur  of  the  Sierra  Nevada  than  is  usually  obtained  by  visitors  to  the 
Yosemite  will  find  himself  amply  rewarded.  The  highest  point  of  the 
Mount  Hoffmann  Range  is  about  four  miles  northeast  of  Porcupine 
Flat,  and  there  are  no  difficulties  of  any  kind  to  be  encountered  in 
reaching*  it. 


0 


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OF  THE 

UNIVERSITY  OF  ILLINOIS 


ZPXj-A-TIE 


THE  OBELISK  GROUP — FROM  PORCUPINE  FLAT. 


425 


THE  HEAD  OF  THE  MERCED  AND  TUOLUMNE  RIVERS. 

Prom  Porcupine  Fiat  we  also  enjoyed  a  magnificent  view  of  the 
great  spur  of  the  Sierra  which  lies  to  the  southeast  of  the  Yosemite, 
and  which  we  called  the  Obelisk  Group,  from  a  high  and  very  conspicu¬ 
ous  peak,  which  rises  in  the  centre  of  the  group,  as  may  be  seen  in 
the  sketch  (Plate  4).  This  is  an  extremely  picturesque  range  of  moun¬ 
tains;  but  it  lias  not  been  explored  by  us.  Mr.  King,  accompanied  by 
Cotter,  started  to  make  an  examination  of  the  group,  during  the  latter 
part  of  October,  1864 ;  but  they  were  driven  back  by  a  severe  snow¬ 
storm  of  several  days’  duration,  having  had  a  very  hard  and  dangerous 
trip. 

From  Porcupine  Flat  we  followed  the  trail  to  Lake  Tenaya,  six 
miles  east-northeast  in  a  direct  line.  This  is  a  beautiful  sheet  of  water, 
a  mile  long  and  half  a  mile  wide.  From  a  high  ridge,  crossed  just 
before  reaching  this  lake,  we  had  a  fine  view  of  a  very  prominent  and 
exceedingly  grand  landmark  through  all  the  region,  and  to  which  the 
name  of  Cathedral  Peak  has  been  given.  As  seen  from  the  west  and 
southwest  it  presents  the  appearance  of  a  lofty  ridge  of  rock,  cut 
squarely  down  for  more  than  a  thousand  feet  on  all  sides,  and  with  a 
cluster  of  pinnacles  at  one  end,  rising  several  hundred  feet  above  the 
rest  of  the  mass.  It  requires  no  effort  of  the  imagination  to  see  the 
resemblance  of  the  whole  to  a  cathedral;  but  the  majesty  of  its  form 
and  its  vast  dimensions  are  such,  that  any  wmrk  of  human  hands  would 
sink  into  insignificance  if  placed  beside  it.  It  is  at  least  2500  feet  above 
the  surrounding  plateau,  and  its  summit  is  11,000  feet  above  the  sea- 
level.  The  wood-cut  (Fig.  70)  gives  but  the  faintest  idea  of  this  won¬ 
derfully  grand  mass  of  rock.* 

At  the  head  of  Lake  Tenaya  is  a  very  conspicuous  conical  knob  of 
bare  granite,  about  800  feet  high,  the  sides  of  which  are  everywhere 
finely  polished  and  grooved  by  former  glaciers.  The  traces  of  the 
existence  of  an  immense  flowT  of  ice  down  the  slopes  of  the  valley, 
from  this  part  of  the  trail  onwards  for  many  miles,  are  exceedingly 
conspicuous.  The  ridges  on  both  sides  of  the  lake  are  worn  and 
grooved  by  glaciers  nearly  up  to  their  summits,  and  travelling  over  the 


*  By  accident,  this  view  was  not  reversed  on  the  wood,  so  that  its  reflection  in  a  mir¬ 
ror  must  be  examined,  to  get  a  correct  idea  of  the  real  position  of  the  peak. 

GEOL.  VOL.  I. — 54 


426 


GEOLOGY  OF  TI1E  SIERRA  NEVADA. 


pass,  from  the  valley  of  the  Tenaya  into  that  of  the  Tuolumne,  became 
very  difficult  for  the  animals,  so  highly  polished  and  slippery  were  the 


Fig*.  70. 


CATHEDRAL  PEAK.  PROM  THE  WEST. 

broad  areas  of  granite  over  which  they  were  obliged  to  cautiously  pick 
their  way.  The  granite  here  has  a  very  coarse  texture,  the  crystals  of 
feldspar  being  often  three  or  four  inches  long.  Above  the  sphere  of 
glacial  action,  these  crystals  project  from  the  weathered  surface  of  the 
rock;  but,  below  that,  they  are  planed  down  to  a  level  with  it,  and 
most  beautifully  polished. 

The  summit  of  the  pass  over  into  the  Tuolumne  Valley  is  9070  feet 
above  the  sea,  and  the  descent  to  the  river  is  only  about  500  feet.  The 
trail  winds  along  under  the  brow  of  the  Cathedral  Peak  Group,  and 
finally  comes  down  to  the  river  near  Soda  Springs,  a  point  which  for 
several  days  we  made  our  head-quarters  while  engaged  in  exploring 
the  vicinity. 

The  Tuolumne  River,  contrary  to  what  is  represented  on  any  pub¬ 
lished  map  of  the  State,*  drains  a  considerably  larger  portion  of  the 

*  The  United  States  linear  surveyors,  in  running  a  line  over  the  Sierra  to  commence 
their  work  in  Mono  Valley,  crossed  the  Tuolumne  River  and  its  branches ;  but  they  sup¬ 
posed  it  to  be  the  San  Joaquin,  and  this  mistake  has  been  perpetuated  on  all  the  maps  up 


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UNIVERSITY  OF  ILLINOIS 


PLATE  "V",  p.  427. 


Unicorn  Peak. 


TIIE  HEAD  OF  THE  MERCED  AND  TUOLUMNE  RIVERS.  427 


Sierra  than  the  Merced,  its  branches  heading  quite  around  and  to  the 
east  of  that  river.  Three  miles  above  Soda  Springs  the  Tuolumne 
forks,  a  large  branch  coming  in  from  the  east  and  another  one  from 
the  southeast.  The  first  of  these  heads  in  the  Mono  Pass  and  at  the 
foot  of  Mount  Dana,  the  culminating  point  of  the  Sierra  in  this  re¬ 
gion  ;  the  other  rises  on  the  north  slope  of  the  Mount  Lyell  Group, 
about  twenty  miles  farther  south. 

The  Upper  Tuolumne  flows  through  a  beautiful  valley,  from  half  a 
mile  to  a  mile  wide  and  about  fifteen  long.  It  is  covered  with  a  ver¬ 
dant  carpet  of  carices,  forming  a  turf,  and  has  a  scattered  growth  of 
pines  (P.  contorta  and  P.  Balfouriana ),  and  spruce  (Abies  Williamsonii). 
Soda  Springs  is  about  nine  miles  from  the  head  of  the  valley,  and  six 
above  the  point  where  the  river  enters  a  deep  and  almost  inaccessible 
canon.  At  the  springs,  which  are  thirty  or  forty  feet  above  the  level 
of  the  river,  the  elevation  of  the  valley  above  the  sea-level  is  8680  feet, 
and  our  camp  nine  miles  farther  up,  at  the  head  of  the  valley  and  the 
foot  of  the  Mono  Pass,  was  9805  feet  in  elevation. 

From  our  camp  at  Soda  Springs  the  view  was  a  magnificent  one. 
The  Cathedral  Peak  Group,  on  the  south  side  of  the  valley,  was  the 
most  conspicuous  feature  in  the  scene  (see  Plate  5);  but  from  this  point 
of  view  the  resemblance  to  a  cathedral  is  not  by  any  means  as  striking 
as  it  was  on  the  west  side.  The  spires  now  become  the  most  promi¬ 
nent  objects,  and  they  are  seen  to  be  two  bare  pyramidal  peaks  rising 
precipitously  from  the  forest-clothed  sides  of  the  ridge,  to  the  height  of 
about  2800  feet  above  the  valley.  Farther  east  the  range  is  continued 
in  a  line  of  jagged  peaks,  too  steep  to  allow  the  snow  to  remain  upon 
them,  and  rising  above  great  slopes  of  bare  granite,  over  which, 
through  the  whole  summer,  in  sheltered  places,  large  fields  of  snow  are 
distributed.  A  very  prominent  peak,  with  a  peculiar  horn-shaped  out¬ 
line,  was  called  “  Unicorn  Peak.”*  A  view  of  Cathedral  Peak,  from 


to  tills  date,  the  whole  course  of  all  the  upper  portion  of  the  San  Joaquin,  the  Merced, 
and  the  Tuolumne  being  laid  down  entirely  wrong. 

*  Names  are  frequently  given  to  prominent  objects,  by  parties  like  ours,  for  conveni¬ 
ence;  as  where  peaks  are  used  for  topographical  stations.  If  not  named,  they  would 
have  to  be  numbered,  which  would  be  both  awkward  and  inconvenient. 


428 


GEOLOGY  OF  THE  SIERRA  NEVADA 


this  side,  but  a  little  higher  up  in  the  valley,  is  given  in  the  annexed 
wood-cut  (Fig.  71).  It  is,  from  all  sides,  a  singularly  attractive  object. 


Fig.  71. 


CATHEDRAL  PEAK.  FROM  THE  NORTH. 


The  Soda  Springs  cover  quite  an  extensive  area,  and  have  a  copious 
flow  of  water,  which,  at  the  time  of  our  visit,  July,  1863,  had  a  tem¬ 
perature  of  46°  to  47°.  There  is  a  continual  escape  of  carbonic  acid 
gas  over  the  surface,  the  water  resembling  in  taste  that  of  the  “  Con¬ 
gress  Spring,”  at  Saratoga.  It  is  a  mild  aperient,  and  might  become 
of  importance,  were  it  not  situated  in  rather  too  high  a  region  to  he 
visited  by  invalids. 

The  vicinity  of  Soda  Springs  and,  indeed,  the  whole  region  about 
the  head  of  the  Upper  Tuolumne  is  one  of  the  finest  in  the  State  for 
studying  the  traces  of  the  ancient  glacier  system  of  the  Sierra  Nevada. 


The  valleys  of  both  the  forks — that  heading  in  the  Mono  Pass  and  the 
one  coming  down  from  the  north  slope  of  Mount  Lyell — exhibit  abun- 


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PLATE  VI,  p.  429. 


CATHEDRAL  PEAK  GROU  P — U  PPER  TUOLUMNE  VALLEY 


THE  HEAD  OF  THE  MERCED  AND  TUOLUMNE  RIVERS. 


429 


dant  evidences  of  having,  at  no  very  remote  period,  been  tilled  with  an 
immense  body  of  moving  ice,  which  has  everywhere  rounded  and  pol¬ 
ished  the  surface  of  the  rocks  up  to  the  height  of  at  least  a  thousand 
feet  above  the  present  level  of  the  river  at  Soda  Springs.*  This  polish 
extends  over  a  vast  area,  and  is  so  perfect  that  the  surface  is  often  seen 
from  a  distance  to  glitter  with  the  light  reflected  from  it  as  from  a 
mirror.  Not  only  have  we  these  evidences  of  the  former  existence  of 
glaciers,  but  all  the  phenomena  of  the  moraines — lateral,  medial,  and 
terminal — arc  here  displayed  on  the  grandest  scale. 

To  the  north  of  Soda  Springs,  a  plateau  stretches  along  the  south¬ 
western  side  of  the  crest  of  the  Sierra,  with  a  gentle  inclination  to¬ 
wards  the  river.  It  is  about  four  miles  wide  from  northeast  to  south- 
west,  and  six  or  seven  miles  long  parallel  with  the  range.  This  plateau 
lies  at  an  elevation  of  between  9000  and  10,000  feet.  It  has  clumps  of 
Finns  contortci  scattered  over  it,  and  is  furrowed  by  water-courses, 
which  are  generally  less  than  fifty  feet  deep.  The  whole  surface  of 
this  is  most  beautifully  polished  and  furrowed,  except  where  covered 
with  piles  of  debris,  which  stretch  across  it  in  long  parallel  lines,  and 
which  are  the  medial  moraines  of  the  several  side-glaciers  which  for¬ 
merly  came  in  to  the  main  one  of  the  valley,  from  the  numerous  gorges 
and  amphitheatres  of  the  great  mass  of  the  Sierra  behind.  Plate  6 
also  shows  one  of  these  broad  surfaces  of  polished  granite,  over  and 
around  which  the  glacier  once  extended,  while  above  and  in  the  dis¬ 
tance  is  the  range  of  Cathedral  and  Unicorn  Peaks,  which  from  this 
point  of  view  exhibits  in  the  most  striking  manner  the  peculiar  pinna- 

.cled  form  of  the  culminating  granitic  summits.  There  is  a  greater 

* 

amount  of  snow  represented  in  the  drawing  than  was  to  be  seen  at  the 
time  of  our  visit,  but  not  more  than  may  usually  be  found  during  the 
earlier  summer  months. 

About- a  mile  below  Soda  Springs  are  the  remains  of  a  terminal 
moraine,  stretching  across  the  valley.  It  is  not  very  conspicuous, 
except  from  the  fact  that  it  bears  a  scattered  growth  of  pines,  contrast- 


*  These  glacial  markings  were  first  noticed  by  Mr.  .T.  E.  Clayton,  and  the  fact  of  their 
existence  was  communicated  by  him  to  the  California  Academy  of  Natural  Sciences,  sev¬ 
eral  years  ago. 


f 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


430 


ing  beautifully  with  the  grassy  and  level  area  above  and  below.  A 
mile  and  a  half  lower  down,  a  belt  of  granite,  a  mile  or  more  wide, 
stretches  across  the  valley ;  over  this  the  river  falls  in  a  series  of  rapids, 
having  a  perpendicular  descent  of  above  a  hundred  feet  in  all.  Below 
this  is  another  grassy  flat,  which  extends  down  to  the  entrance  of  the 
canon.  This  granite  belt  is  worn  into  many  knobs,  some  of  which  are 
a  hundred  feet  high  and  over;  between  these  there  arc  great  grooves 
and  channels,  and  their  whole  surface,  to  the  very  summit,  is  grooved 
and  polished,  the  markings  being  parallel  with  the  present  course  of 
the  river. 

The  annexed  wood-cut  (Fig.  72)  is  a  not  very  successful  attempt  to 
exhibit  the  appearance  of  this  glacier-polished  ridge.  Beyond  it,  and 


Fig.  72. 


Cathedral  Peak. 


GLACIER-POLISHED  SURFACES  IN  TUOLUMNE  VALLEY. 


in  the  background,  is  the  range  of  Cathedral  Peak,  and  the  peak  itself, 
of  which  the  double  summit  is  no  longer  recognizable  from  this  direc¬ 
tion. 


THE  11 E  A 1)  OF  THE  MEKCEl)  AND  TUOLUMNE  RIVERS 


431 


Just  below  this  is  an  isolated  granite  knob,  rising  to  a  height  of 
about  800  feet  above  the  river,  and  beautifully  polished  to  its  very 
summit.  At  this  point,  the  great  glacier  of  the  Tuolumne  must  have 
been  at  least  a  mile  and  a  half-  wide,  and  over  1000  feet  thick.  From 
this  knob  the  view  of  the  valley  and  the  surrounding  mountains  is  one 
of  hardly  surpassed  interest  and  grandeur.  In  the  lower  part  of  the 
valley  are  the  smooth  and  glittering  surfaces  of  granite  indicating  the 
former  existence  of  the  glacier;  above  this,  on  either  hand,  the  steep 
slopes  of  the  mountains,  clad  with  a  sombre  growth  of  pines  ( Pinas 
contorta) ;  and  beyond,  and  still  higher  up,  the  great  snow-lields,  above 
which  rise  the  Unicorn  and  many  nameless  pinnacles  and  peaks,  in 
grand  contrast  with  the  dome-shaped  masses  seen,  in  the  farthest  dis¬ 
tance,  in  the  direction  of  Lake  Tenaya. 

At  the  head  of  the  south  branch  of  the  Tuolumne,  which  unites  with 
the  other  three  miles  above  Soda  Springs,  is  a  grand  mass  of  moun¬ 
tains,  to  which  we  gave  the  name  of  the  Mount  Lyell  Group,  calling 
the  highest  peak  after  that  eminent  geologist.  In  this  group,  and 
within  a  circle  only  three  or  four  miles  in  diameter,  four  of  the  princi¬ 
pal  rivers  of  California  have  their  sources;  these  are  the  Merced,  Tuo¬ 
lumne,  San  Joaquin,  and  Owen’s  Rivers. 

The  fine  wood-cut  (Plate  7,  the  frontispiece  to  this  volume),  drawn 
by  H.  Fenn,  from  a  sketch  by  Mr.  Hoffmann,  will  give  a  good  idea 
of  the  grand  appearance  of  this  truly  Alpine  range. 

The  culminating  point  of  the  Mount  Lyell  Group  was  ascended  by 
Messrs.  Brewer  and  Hoffmann ;  but  they  were  unable  to  reach  the 
very  summit,  which  was  found  to  be  a  sharp  pinnacle  of  granite  rising 
up  above  the  snow.  \By  the  observations  taken  at  a  point  estimated 
to  be  150  feet  below  the  top  of  this  pinnacle,  Mount  Lyell  is  calculated 
to  be  13,217  feet  high,  or  only  ten  feet  less  than  Mount  Dana.  As  we 
had  no  station  barometer  nearer  than  Stockton  on  the  day  of  the 
ascent,  the  result  is  only  to  be  considered  an  approximation.  As  near 
as  could  be  made  out  with  the  pocket-level  from  Mount  Dana,  Mount 
Lyell  was  a  little  the  lower  of  the  two.  The  annexed  sketch  (Fig.  73) 
will  give  an  idea  of  the  form  of  the  summit  of  this  grand  mountain. 

The  culminating  peaks  of  Mount  Lyell  have  a  gradual  slope  to  the 
northeast;  but,  to  the  south  and  southwest,  they  break  oft* in  precipices 


GEOLOGY  OF  THE  SIERRA  NEVADA 


a  thousand  or  more  feet  in  height.  Between  these  cliffs,  on  that  side, 
a  vast  amphitheatre  is  included,  once  the  birthplace  of  a  grand  gla- 

Fig.  73. 


SUMMIT  OF  MOUNT  LYELL. 


cier,  which  flowed  down  into  the  canon  of  the  Merced.  Several  other 
former  heads  of  glaciers  were  seen  in  various  directions,  and  traces  of 
their  action  were  observed  up  to  within  a  thousand  feet  of  the  crest. 

On  the  north  slope  of  Mount  Lyell,  and  among  the  peaks  one  or  two 
miles  northwest  of  the  summit,  there  are  outcrops  of  a  highly  meta- 
morpliic  slate,  the  continuation  of  the  belt  which  is  so  conspicuous  on 
Mount  Dana.  Want  of  time  rendered  it  impossible  for  the  party  to 
make  any  detailed  examination  of  the  rocks  in  this  group. 

From  the  high  points  around  Mount  Lyell,  a  fine  view  was  obtained 
of  the  extension  of  the  range  of  the  Sierra  to  the  southeast.  There 
are  hundreds  of  peaks,  in  that  direction,  which  rise  to  an  elevation  of 
over  12,000  feet.  Most  of  these  are  sharp  pinnacles  of  granite,  tower¬ 
ing  above  extensive  snow-fields,  with  small  plateaus  between  them. 
Fifteen  or  twenty  miles  south,  the  chain  appears  to  sink  considerably, 
the  average  height  of  the  dominating  peaks  being  from  one  to  two 
thousand  feet  less  than  it  is  about  Mount  Lyell.  This  region  is,  as  yet, 
entirely  unexplored.  Traces  of  an  old  Indian  trail  were  discovered, 


THE  HEAD  OF  THE  MERCED  AND  TUOLUMNE  RIVERS.  433 


however,  leading  from  the  ridge  at  the  head  of  the  Tuolumne  over  into 
the  valley  of  Owen’s  River. 

Avalanches  of  snow  are  frequent  on  the  steep  mountain  sides  in  this 
region.  They  start  on  the  slopes,  above  the  limits  of  the  forests,  and 
sweep  down  with  irresistible  force,  crushing  the  trees  which  lie  in  their 
paths,  and  carrying  large  masses  of  rocks  and  soil  with  them.  The 
amount  of  snow  brought  down  by  one  of  these  slides  is  so  great  some¬ 
times,  that  years  are  required  for  the  mass  accumulated  at  the  bottom 
to  melt  away. 

The  Mono  Pass  is  at  the  head  of  the  more  northerly  of  the  two  forks 
of  the  Tuolumne  which  unite  a  little  above  Soda  Springs.  From  the 
springs  to  the  summit  of  the  pass  is  twelve  miles  in  a  direct  line,  and 
about  fourteen  by  the  trail,  which  follows  the  river  all  the  way.  For 
exploring  the  region  in  this  vicinity,  our  camp  was  fixed  for  several 
days  at  a  point  about  three  miles  from  the  summit,  on  the  left  bank  of 
the  stream,  and  near  the  junction  of  a  small  branch  coming  in  from 
the  slopes  of  Mount  Dana  to  unite  with  the  main  fork,  which  heads  in 
the  pass  itself  and  along  the  ridge  to  the  southeast  of  it.  This  camp 
was  9805  feet  above  the  sea,  and  about  a  thousand  feet  below  the  sum¬ 
mit,  which  is  10,765  feet  in  height,  this  being  the  most  elevated  pass 
in  actual  use  within  our  territory,  and,  so  far  as  we  know,  in  North 
America.  There  are  higher  passes  in  the  more  southern  portion  of  the 
Sierra ;  but  these  are  very  rarely  crossed  by  travellers,  and  can  hardly 
be  said  to  be  in  use. 

The  highest  crest  of  the  Sierra,  in  the  region  of  the  Mono  Pass,  is 
along  the  extreme  eastern  edge  of  the  range,  the  distance  from  Mount 
Dana  to  Mono  Lake  being  but  little  over  six  miles,  and  the  descent  no 
less  than  6773  feet,  or  over  a  thousand  feet  to  the  mile.  The  culminat¬ 
ing  ridge,  to  the  north  of  the  pass,  is  crowned  by  a  series  of  elevations, 
which  have  rounded  summits  and  rather  gently  sloping  sides,  contrast¬ 
ing  in  the  most  marked  way  with  the  pinnacles  and  obelisks  of  the 
central  portion  of  the  range.  The  geological  cause  of  this  condition 
of  things  is  to  be  found  in  the  fact  that  the  very  highest  part  of  the 
Sierra,  through  a  considerable  distance  to  the  north  of  the  Mono  Pass, 
is  not  granitic,  but  made  up  of  metamorphic  slates,  which,  as  they 
decompose,  give  a  very  different  aspect  to  the  scenery  from  that  pro- 


GEOL.  VOL.  I. — 55 


434 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


duced  by  the  weathering  of  the  granites  and  lavas  which  usually  form 
the  crest  of  the  chain. 

This  belt  of  metamorphic  rock  is  three  or  four  miles  wide  at  the 
pass,  and  its  junction  with  the  granite  is  very  distinct  and  well-defined 
wherever  the  two  formations  are  exposed  in  contact  with  each  other. 
The  relative  position  of  the  granite  and  the  slates  was  carefully  exam¬ 
ined  for  several  miles  along  the  ridge  south  of  our  camp  in  the  pass, 
and  about  1200  feet  above  it.  The  metamorphic  rock  here  is  chiefly  a 
mica-slate,  passing  into  a  silicious  variety  of  the  same.  It  is  quite  evenly 
and  thinly  bedded  in  some  places ;  other  portions  are  apparently  more 
metamorphosed  and  less  distinctly  stratified.  The  dip  of  the  slates 
was  found,  all  along  this  ridge,  to  be  at  a  very  high  angle,  and  always 
to  the  east  and  northeast,  or  away  from  the  axis  of  the  chain.  The 
granite  was  observed,  in  many  places,  to  have  penetrated  the  slates  in 
ramifying  veins ;  but  there  was  nothing  seen  indicating  a  passage  of 
one  rock  into  the  other.  The  direction  of  the  strata  is  nearly  that  of 
the  chain  itself,  or  about  30°  W. 

In  the  pass  itself  the  slates  also  dip  to  the  northeast,  the  strata  being 
in  places  much  contorted;  but  the  junction  of  the  two  formations  is 
perfectly  well-defined.  A  little  east  of  the  summit  there  is  a  belt  of  a 
red,  scoriaceous  rock ;  this,  however,  does  not  appear  to  be  of  volcanic 
origin,  but,  rather,  a  mass  of  ferruginous  slate  which  has  become  con¬ 
siderably  decomposed,  after  having  been  imperfectly  metamorphosed. 

Directly  north  of  the  pass,  a  rounded  summit  rises  to  the  height  of 
about  12,000  feet;  it  is  probably  metamorphic.  Between  this  and 
Mount  Dana  is  another  gap,  somewhat  lower  than  the  Mono  Pass,  but 
which  is  not  used  for  a  trail  or  road,  because  the  descent  on  the  east 
side  is  too  precipitous  to  allow  it  to  be  traversed  with  animals  without 
extensive  excavation.  There  is  also  another  gap  on  the  north  side  of 
Mount  Dana,  which  is  called  MacLane’s  Pass;  it  is  about  600  feet 
lower  than  the  Mono  Pass,  and  has  been  examined,  in  behalf  of  the 
county,  by  a  committee  appointed  to  search  out  a  better  route  than  the 
present  one  across  the  mountains,  in  this  vicinity ;  what  conclusion 
was  arrived  at  we  have  not  ascertained. 

Plate  8  will  serve  to  give  an  idea  of  the  appearance  of  the  crest  of 
the  Sierra  to  the  north  of  Mono  Pass ;  it  was  taken  from  a  point  a  little 


CREST  OF  THE  SIERRA,  LOOKING  EAST  FROM  ABOVE  SODA  SPRINGS. 


iiia  anv-ici 


LI8RARY 
OF  THE 

UNIVERSITY  OF  ILLINOIS 


THE  HEAD  OF  THE  MERCED  AND  TUOLUMNE  RIVERS.  435 


above  Soda  Springs.  The  mountain  on  the  left  is  Mount  Dana.  The 
tirst  depression  on  the  right,  or  south,  is  the  gap  noticed  above  as  hav¬ 
ing  too  precipitous  a  descent  on  the  east  side  to  be  used  as  a  pass. 
The  present  trail,  or  the  Mono  Pass,  winds  around  and  behind  the 
rocks  in  the  middle  ground  of  the  sketch,  and  crosses  the  mountains  at 
its  extreme  right.  The  lower  cliffs,  in  the  centre,  are  of  granite,  and 
are  most  beautifully  polished  by  glaciers. 

Mount  Dana,  as  already  remarked,  is  the  culminating  point  of  the 
Sierra  in  this  region,  and  there  is  no  higher  one  north  as  far  as  Mount 
Shasta,  or  south  until  we  reach  the  high  peak  to  which  we  gave  the 
name  of  Mount  Goddard.  The  mass  of  this  mountain  is  of  metamor- 
phic  slate,  extremely  contorted,  but  having  a  general  dip  to  the  north¬ 
east.  The  rock,  especially  on  the  south  side,  is  made  up  of  alternating 
bands  of  a  bright  green  (sandstone  passing  into  epidote-rock)  and  deep 
reddish-brown.  The  effect  of  this  contrast  of  colors  is  very  pleasing, 
especially  where  the  surface  is  wet,  so  as  to  bring  out  the  different 
shades. 

The  view  from  the  summit  of  Mount  Dana  is  a  very  extensive  one ; 
and,  as  the  ascent  can  be  made  without  difficulty,  all  tourists  who 
have  any  desire  to  learn  something  of  the  grandeur  of  California 
scenery  should  not  fail  to  climb  at  least  this  one  high  point.  The 
innumerable  ranges  and  peaks  of  the  Sierra  itself,  stretching  off  to  the 
north  and  south,  form,  of  course,  the  great  feature  of  the  view.  To  the 
east,  Mono  Lake  lies  spread  out,  as  on  a  map,  at  a  depth  of  nearly 
7000  feet  below,  while  beyond  it  rise  the  lofty,  and  here  and  there 

0 

snow-clad,  ranges  of  the  Great  Basin,  a  region  of  stupendous  moun¬ 
tains,  possessing  all  the  attractions  of  the  unknown. 

From  the  summit,  the  belt  of  metamorphic  slates  is  seen  to  extend 
off  for  a  great  distance  to  the  northwest,  forming  a  line  of  high  peaks 
with  rounded  outlines.  Of  these  Castle  Peak  is  the  next  prominent 
one  north  of  Mount  Dana,  from  which  it  is  twelve  miles  distant.  This 
peak  is  13,000  feet  high,  as  nearly  as  we  could  estimate  by  levelling 
across  to  it. 

Along  the  western  and  southern  slope  of  Mount  Dana  the  traces  of 
former  glaciers  are  exceedingly  distinct,  up  to  an  altitude  of  12,000 
feet.  In  the  gap  directly  south  of  the  summit  a  mass  of  ice  must  once 


436 


GEOLOGY  OF  THE  SIERRA  NEVADA, 


have  existed,  having  a  thickness  of  at  least  800  feet,  at  as  high  an  ele¬ 
vation  as  10,500  feet.  From  all  the  gaps  and  valleys  of  this  side  of  the 
range,  in  both  directions  from  Mono  Pass,  tributary  glaciers  came 
down,  and  these  all  united  into  one  grand  mass  lower  in  the  valley, 
where  the  medial  moraines  which  accumulated  between  them  are  per¬ 
fectly  distinguishable,  and  in  places  as  regularly  formed  as  any  to  be 
seen  in  the  Alps  at  the  present  day. 

The  trail  down  the  eastern  side  of  the  Mono  Pass  descends  in  what 
is  called  “  Bloody  Canon;”  and  this  is,  at  present,  the  only  practicable 
route  from  the  head  of  the  Tuolumne  over  into  Owen’s  Valley.  It  is 
very  steep  and  rough;  the  name  is  suggestive  of  the  disagreeable 
effects  of  the  sharp  edges  of  the  slates  on  the  legs  of  the  unfortunate 
animals  driven  over  it.  The  perpendicular  descent  is  not  less  than 
4000  feet  in  a  distance  of  three  miles. 

In  descending  this  canon,  considerable  bodies  of  slate  were  observed, 
with  a  dip  towards  the  axis  of  the  chain.  About  a  mile  from  the  sum¬ 
mit  they  become  more  highly  altered,  and  the  stratification  is  nearly 
obliterated,  the  rock  becoming  porphyritic  occasionally.  Two  miles 
east  of  the  summit  of  the  pass,  granite  is  again  met  with  and  continues 
to  the  foot  of  the  canon.  It  is  a  finer-grained  variety  than  that  seen  on 
the  western  side  of  the  mountain,  and  is  of  a  light  rose  color,  and 
largely  made  up  of  quartz. 

Traces  of  ancient  glaciers  are  very  abundant  from  near  the  summit 
to  the  very  foot  of  the  canon.  The  rocks  are  rounded,  polished,  and 
grooved ;  and  there  are  evidences  of  immense  pressure  of  the  mass  of 
ice  against  the  walls,  where  the  canon  is  narrow  and  shut  in  by  high 
precipices  on  each  side.  In  such  places,  and  in  other  localities  where 
there  has  been  a  very  thick  mass  of  ice  resting  upon  the  granite,  the 
structure  of  this  rock  is  changed,  near  the  surface,  as  if  by  the  crush¬ 
ing  and  closely  compacting  together  of  the  different  minerals  of  which 
it  is  made  up,  so  that  a  crust  is  formed,  sometimes  as  much  as  half  an 
inch  thick.  This  crust  seems  to  be  more  durable  than  the  body  of  the 
rock,  and  as  the  granite  weathers  it  scales  off,  sometimes  in  large  flakes, 
with  a  highly  polished  surface  on  one  side,  seemingly  as  fresh  as  if 
made  only  yesterday ;  while  other  portions  of  the  granite,  which  have 


THE  SONORA  PASS. 


40  n 

O  / 

not  been  subjected  to  this  pressure,  are  corroded  to  a  considerable 
depth,  as  is  easily  seen  where  large  areas  of  uneven  rock  are  exposed. 

There  are  several  small  lakes  in  the  canon,  the  lowest  of  which  is 
about  7000  feet  above  the  sea-level,  and  about  a  mile  long.  These 
lakes  have  been  produced  by  the  damming  of  the  gorge  by  the  termi¬ 
nal  moraines  left  by  the  glacier  in  its  retreat.  At  the  lowest  lake,  the 
moraine  rises  about  fifty  feet  above  the  level  of  the  water,  and  extends 
entirely  across  the  canon.  At  the  eastern  base  of  the  mountains,  each 
gorge  or  valley  coming  down  has  long  ridges  of  gravel  and  loose 
materials  extending  out  into  the  plain  for  a  considerable  distance,  indi¬ 
cating  the  position  of  the  glaciers  which  once  found  their  way  down  on 
this  side,  as  well  as  on  the  western  slope.  These  old  moraines  were 
very  conspicuous,  at  a  distance  of  several  miles,  from  the  summits  of 
the  volcanic  cones  near  Mono  Lake. 

Having  devoted  all  the  space  to  the  interesting  district  about  the 
head  of  the  Tuolumne  which  our  limits  will  allow,  we  will  take  up 
next  the  region  at  the  head  of  the  Stanislaus  River,  and  along  the  road 
over  the  Sonora  Pass,  which  is  the  first  travelled  route  across  the  Sierra 
north  of  the  Mono  Pass,  and  the  most  southern  of  the  wagon-roads 
which  have  yet  been  completed,  to  connect  California  with  the  great 
mineral  region  to  the  east. 


Section  V. — The  Sonora  Pass. 

The  following  notes  of  the  region  between  Aurora  and  Sonora,  as 
seen  on  the  Sonora  trail,  were  furnished  by  Professor  Brewer,  and  will 
throw  some  light  on  this  portion  of  the  High  Sierra.  At  the  time  our 
party  crossed  by  this  route  a  wagon-road  was  in  process  of  construc¬ 
tion,  a  large  force  of  men  being  engaged  upon  it;  it  is  now  probably 
opened  through,  but  how  much  it  is  used  by  wheeled  vehicles  at 
present  we  are  not  informed.  Its  value  depends,  in  a  great  degree, 
on  the  future  importance  of  tlie  Esmeralda  mining  region,  as  its  great 
elevation  renders  it  unlikely  that  it  will  be  able  to  compete  with  other 
routes  farther  north,  in  the  trade  with  AYashoe. 

On  leaving  Aurora  by  this  route,  at  about  ten  or  twelve  miles  from 


438 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


the  town,  there  are  several  places  where,  at  a  recent  date,  there  have 
been  extensive  hot  springs,  which  have  had  a  powerful  action  on  the 
surrounding  rocks,  hut  which  are  now  extinct.  The  “  Meadows”  on 
Walker’s  River,  through  which  the  road  passes,  is  a  basin,  quite  level 
and  surrounded  by  mountains;  it  is  from  six  to  eight  miles  long  and 
three  or  four  wide,  hut  has  little  good  forage  upon  it.  A  large  branch 
of  Walker’s  River  passes  through  it,  and  several  smaller  streams  come  in 
from  the  mountains  on  the  west.  The  distance  from  the  Meadows  to 
the  summit  of  the  pass  is  estimated  at  twenty-six  miles,  and  two  con¬ 
siderable  branches  of  Walker’s  River  are  crossed  on  the  road.  Between 
these  two  there  is  a  copious  thermal  spring,  the  water  of  which  is  nearly 
at  a  boiling  temperature,  and  slightly  saline  ;  it  evolves  a  large  amount 
of  carbonic  acid  gas.  A  large  quantity  of  calcareous  tufa  is  deposited 
about  it,  and  still  more  exists  on  the  sides  of  the  hill,  higher  up,  show¬ 
ing  where  formerly  other  and  more  copious  springs  once  discharged 
themselves.  Granite  and  lava  form  the  predominating  rocks  in  this 
vicinity;  but  the  exact  boundaries  of  the  two  could  hardly  be  defined 
without  more  accurate  maps  than  we  have  yet  at  our  command.  The 
altitude  of  the  Meadow  is  about  6500  feet  above  the  sea,  and  of  the  hot 
springs,  7334  feet. 

The  second  fork  of  Walker’s  River  is  thirty-six  miles  from  Aurora; 
and  where  the  road  crosses  it  there  is  a  basin  which  has  evidently  once 
been  a  lake.  Two  large  branches  unite  a  short  distance  north  of  the 
trail,  and  together  flow  through  a  deep  canon,  while  the  region  above, 
extending  for  several  miles  up  both  streams,  was  evidently  a  lake, 
which  became  partially  filled  up  with  the  detritus  washed  in  from  the 
surrounding  mountains ;  afterwards,  the  removal  or  cutting  through  of 
the  barrier  by  which  the  lake  was  dammed  up  being  effected,  the  accu¬ 
mulated  materials  in  its  bottom  were  gradually  denuded  into  their  pre¬ 
sent  form.  Deep  arroyos  are  cut  into  this  deposit,  and  these  are  most 
beautifully  terraced,  especially  on  the  western  branch,  where  in  places 
as  many  as  eight  or  ten  benches  may  be  traced*  Of  these  two  are 
more  conspicuous  than  the  others,  and  the  highest  one  was  estimated  at 
about  1000  feet  above  the  river. 

The  party  encamped  (Camp  125)  at  a  small  lake  about  forty-two 
miles  trom  Aurora,  near  the  western  branch  of  the  river,  and  from  here 


TIIE  SONORA  PASS. 


439 


ascended  a  high  point  to  the  north,  from  which  a  fine  view  was  ob¬ 
tained.  The  elevation  of  the  camp  was  7282  feet  above  the  sea,  that 
of  the  point  ascended,  9739.  From  its  summit,  peaks  are  seen  to  the 
north-northwest,  much  higher,  and  apparently  of  volcanic  materials. 
Another  high  volcanic  mass,  with  some  snow  upon  it,  was  seen  in  a 
direction  A.  49°  E. ;  the  upper  part  of  this  was  bare  of  vegetation,  and 
covered  with  ashes,  lying  upon  very  steep  slopes,  like  the  volcanic 
materials  on  the  cones  south  of  Mono  Lake. 

AH  the  rock  seen  in  this  vicinity  was  volcanic,  and  the  same  was  the 
case  as  far  as  the  west  fork  of  the  Walker,  two  miles  beyond  Camp 
125,  where  the  stream  was  crossed  at  an  elevation  of  about  7000  feet 
above  the  sea.  Hear  the  crossing  on  the  east  side,  and  north  of  the 
trail,  are  several  hills  or  knobs  of  basaltic  lava,  distinctly  bedded  and 
most  beautifully  columnar,  the  columns  always  at  right-angles  to  the 
bedding;  although  the  beds  themselves  lie  at  all  angles,  from  horizon¬ 
tal  to  perpendicular.  Soon  after  crossing  this  branch,  mica-slate  is  met 
with,  forming  a  narrow  belt,  dipping  northeast,  and  traversed  by  veins 
of  granite.  Beyond  this,  granite  makes  its  appearance  and  continues 
to  be  the  only  rock  seen  on  the  pass  nearly  to  the  town  of  Sonora,  far 
down  on  the  western  slope,  except  that  in  places  it  is  covered  by  volca¬ 
nic  accumulations.  In  the  valley  up  which  the  trail  passes  few  glacier 
markings  were  seen,  until  within  two  miles  of  the  summit,  when  they 
became  very  conspicuous. 

The  Sonora  Pass  has  two  summits,  the  eastern  forming  the  water¬ 
shed  and  being  9607  feet  above  the  sea;  the  western  one  is  higher,  its 
altitude  being  10,115  feet,  according  to  our  measurements.  All  about 
the  eastern  summit  the  granitic  rocks,  which  form  the  mass  of  the 
mountains,  are  covered  with  beds  of  lava,  which  has  flowed  out  in 
sheets  over  the  uneven  and  irregularly  denuded  surface  of  the  granite, 
and  both  lava  and  granite  have  undergone  considerable  erosion  since 
the  former  was  erupted,  so  that  the  volcanic  materials  lie  in  irregular 
and  uneven  masses.  Ho  craters  were  observed  here,  and  it  appears 
that  the  lava  has  issued  from  fissures  in  the  granite,  forming  dykes,  of 
which  many  examples  were  seen  near  the  pass.  One  about  a  mile  east 
of  the  western  summit,  and  near  the  trail,  shows  the  relation  of  the 
two  formations  very  well.  The  granite  is  reddened  and  softened  near 


440 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


its  junction  with  the  lava,  as  is  seen  in  a  great  many  places  in  the 
Sierra. 

North  of  the  pass  are  high  and  sharp  peaks  of  bedded  lava,  which 
were  not  ascended ;  others  to  the  south  were  examined,  and  one  was 
measured  and  found  to  he  11,643  feet  above  the  sea;  one  or  two  other 
points  about  a  mile  farther  to  the  south  were  about  150  feet  higher 
than  this.  Glacial  scratches  were  seen  nearly  to  the  summit  of  the 
most  elevated  ridges.  To  the  west  and  northwest  of  the  pass,  masses 
of  granite  and  lava  alternate  with  each  other,  as  far  as  the  eye  can 
reach,  and  very  lofty  and  rugged  peaks  of  granite  were  noticed  to  the 
west  of  Castle  Peak,  which  is  seven  miles  southeast  of  the  eastern 
summit;  this  for  a  long  time  was  considered  the  highest  peak  of  the 
Sierra  and  the  loftiest  mountain  in  the  State,  except  Mount  Shasta. 

The  two  summits  of  the  pass  are  about  three  miles  apart,  and  the 
Stanislaus  River  heads  at  the  eastern ;  but,  in  descending  from  the 
valley  between  the  summits,  it  runs  through  a  deep  canon,  as  yet 
impassable  for  animals.  Through  this  it  was,  in  1863,  proposed  to  con¬ 
struct  a  road,  thus  avoiding  the  western  and  higher  summit  altogether. 

In  going  west,  the  trail  follows  the  Stanislaus  River  for  nineteen 
miles  from  the  western  summit.  The  valley  keeps  in  the  granite  all 
the  way,  but  lava  caps  the  hills  on  both  sides,  the  canon  being  cut 
down  deep  into  the  underlying  rock.  Several  dykes  of  basaltic  lava 
were  seen,  showing  how  the  volcanic  material  had  found  its  way  to  the 
surface.  The  region  is  covered  with  open  forests,  and  there  is  but 
little  forage,  only  one  grassy  flat,  called  Onion  Valley,  being  seen;  this 
is  about  ten  miles  west  of  the  summit. 

Camp  127  was  made  at  the  lower  crossing  of  the  Stanislaus,  about 
eighteen  miles  from  the  pass,  and  at  an  elevation  of  5454  feet,  the  river 
at  the  bridge  being  5405  feet  above  the  sea.  From  this  camp  some  ex¬ 
amination  was  made  of  the  mountains  to  the  south.  The  sides  of  the 
canon  rise  abruptly  to  the  height  of  from  2500  to  3000  feet,  granite 
forming  the  mass  and  extending  up  to  within  700  feet  of  the  summit; 
above  that  point  it  was  covered  with  rudely  columnar  basaltic  lava. 
Higher  mountains  were  seen  on  every  side,  all  of  granite  capped  with 
lava.  On  the  ridges  lying  between  the  forks  of  the  Stanislaus,  to  the 
north,  these  were  exceedingly  grand,  rising  to  about  3500  feet  above 


THE  SONORA.  PASS 


441 


the  river,  and  having  their  summits  worn  into  fantastic  forms;  one,  of 
which  a  wood-cut  is  given  (Fig.  74),  resembled  an  immense  castle 
crowning  the  bald  mountain  of  granite. 


Fig.  74. 


SUMMITS  CAPPED  WITH  LAVA,  ON  THE  SONORA  ROAD. 

Another  sketch  (Fig.  75)  gives  a  view  of  a  ridge  of  similar  character 
in  the  same  vicinity,  showing,  however,  only  the  volcanic  capping, 


Fig.  75. 


VOLCANIC  RIDGE  ON  THE  SONORA  ROAD. 


which  appears  like  the  ruins  of  a  gigantic  wall.  There  is  an  almost 
endless  variety  of  these  very  picturesque  masses,  of  which  the  dark 
and  sombre  color  contrasts  admirably  with  the  lighter  tint  of  the  under¬ 
lying  granite. 

GEOL.  VOL.  I. — 56 


442 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


The  ridge  of  lava  which,  was  ascended  was  found  to  have  on  its  sum- 
mit  ten  or  twelve  boulders  of  granite,  of  coarse  texture,  containing 
large  crystals  of  feldspar;  some  of  these  were  angular,  others  worn 
and  rounded.  One  of  them,  which  was  perched  on  a  sharp  ridge  of 
lava,  was  found  to  be  seventeen  'feet  long,  fourteen  wide,  and  twelve 
high ;  the  others  were  smaller.  Another  lava  spur,  a  quarter  of  a 
mile  east  of  this,  had  its  summit  strewn  with  similar  masses  of  gran¬ 
ite.  They  must  have  come  from  the  main  ridge  of  the  Sierra  to 
the  east,  in  which  direction,  at  a  distance  of  three  or  four  miles,  there 
is  granite  at  a  higher  elevation  than  that  of  the  boulders  observed,  and 
it  seems  clear  that  these  must  have  been  transported  by  glaciers  to 
their  present  position,  as  no  other  cause  can  be  conceived  of  as  possi¬ 
ble.  This  would  indicate  an  immense  thickness  for  the  glacial  mass 
capping  the  Sierra  during  the  ^ice-period;”  but  the  former  existence 
of  glaciers  from  1000  to  2000  feet  thick,  in  other  parts  of  the  range, 
has  been  proved  by  the  clearest  evidence. 

From  the  Stanislaus  River  to  Sonora,  the  distance  is  called  forty-six 
miles.  At  the  lower  crossing  there  are  well-defined  terraces,  one  on 
the  northern  and  two  on  the  southern  side  of  the  river;  the  highest  of 
these  is  about  100  feet  above  the  water. 

From  the  river  the  trail  ascends  the  ridge  on  the  south  side,  and  fol¬ 
lows  down  the  divide  between  the  Stanislaus  and  the  Tuolumne  Rivers, 
on  a  volcanic  table,  for  some  twenty  miles  or  more,  the  lava  covering 
the  surface  everywhere  except  when  cut  into  by  erosion,  so  as  to  expose 
the  underlying  granite,  A  correct  topographical  map  on  a  very  large 
scale  would  be  required  to  show  the  exact  position  of  all  the  lava 
masses  on  this  route.  Much  of  the  material  is  a  hard  basaltic  lava,  but 
there  is  also  a  large  amount  of  volcanic  breccia,  or  fragments  of  vol¬ 
canic  rock  thrown  promiscuously  together  and  cemented  by  finer  mate¬ 
rials  of  the  same  kind.  Before  reaching  Strawberry  Flat  the  granite 
is  seen  weathered  out  into  immense  rounded,  boulder-like  masses. 
About  fourteen  miles  from  Sonora  is  the  “  Sugar  Pine  District,”  where 
are  valuable  and  important  mines  of  auriferous  quartz  in  the  granite, 
as  has  been  already  noticed.  The  rock  along  the  lower  part  of  the 
trail  towards  Sonora  becomes  softer,  and  by  its  decomposition  furnishes 


THE  HEAD  OF  THE  MOKELUMNE  RIVER. 


443 


a  redder  soil  than  that  derived  from  the  harder  granite  farther  up  in 
the  mountains.  It  bears  gold,  and  placer  diggings  are  extensively  dis¬ 
tributed  over  it. 


Section  VI.  —  The  Head  of  the  Mokeluaine  River.  The  Road 
from  the  Calaveras  Bio  Trees  to  Silver  Mountain. 


In  continuing  the  account  of  our  rapid  reconnaissance  of  the  High 
Sierra,  we  come  next  to  the  region  about  the  head  of  the  Mokelumne, 
to  reach  which  we  followed  up  the  road  from  Murphy’s,  by  the  Calave¬ 
ras  Group  of  Big  Trees,  to  Silver  Mountain,  which  is  not  only  the 
name  of  one  of  the  higher  peaks  of  the  range,  but  is  also  that  of  a 
mining  town,  where  there  was,  in  1863,  considerable  mining  and  pros¬ 
pecting  going  on,  in  what  was  supposed  by  many  to  be  an  important 
silver  district.  A  good  wagon-road  was  then  constructing  from  the 
Big  Trees  across  to  the  town  of  Silver  Mountain,  and  which  was  to 
connect  with  the  mining  districts  near  Aurora  and  Virginia  City.  The 
region  about  Silver  Mountain  was  formerly  included  within  the  coun¬ 
ties  of  Amador  and  Calaveras,  there  being  some  uncertainty  in  regard 
to  its  real  position  with  reference  to  the  county  lines  ;  it  has  since  been 
set  off  as  a  separate  organization,  and  called  Alpine  County. 

Mr.  Wackenreuder  has  been  engaged  in  making  for  the  Survey  a 
topographical  reconnaissance  of  the  region  from  Silver  Mountain  north¬ 
wards,  as  far  as  the  Downieville  Buttes,  and  his  map  has  just  been 
completed,  but  not  in  time  to  allow  of  its  being  consulted  in  the  pre¬ 
paration  of  this  abstract  of  the  geology  of  the  region.  The  informa¬ 
tion  contained  on  Mr.  Wackenreuder’s  map  will  be  incorporated  in 
our  map  of  Central  California,  now  in  process  of  construction  at  the 
office  of  the  Geological  Survey. 

The  road  to  Silver  Mountain  passes  through  the  famous  grove  of  the 
Big  Trees  of  Calaveras  County,  which  is  about  twenty  miles  from 
Murphy’s,  and  2550  feet  above  that  mining  town,  the  elevation  of  the 
floor  of  the  hotel  at  the  Big  Trees  being  4759  feet  above  the  sea,  and 
that  of  Sperry’s  Hotel,  at  Murphy’s,  2201  feet. 

The  Calaveras  Grove  is  the  one  chiefly  visited  by  tourists,  on  account 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


of  its  proximity  to  the  settled  part  of  the  State,  and  because  there  are 
good  accommodations  for  travellers,  which  is  not  the  case  at  any  other 
locality  where  these  trees  are  growing.  It  is  now  well  known,  from 
information  collected  by  the  Survey,  that  instead  of  there  being  only  a 
few  isolated  groves  of  Big  Trees  in  the  State,  there  is  a  belt  of  them 
dotted  along  at  intervals  on  the  western  slope  of  the  Sierra,  from 
Tulare  to  Calaveras  County,  and  at  an  elevation  of  from  5000  to  7000 
feet.  The  species  is  undoubtedly  very  limited  in  its  range,  and  is 
strictly  confined  to  the  State  of  California.  Specimens  of  it  may  be 
found  in  every  stage  of  growth;  and,  as  before  noticed,  the  smaller  ones 
are  sawn  up  for  lumber  at  Thomas’s  Mill,  above  Visalia. 

The  Big  Trees  are,  indeed,  among  the  greatest  wonders  of  Califor¬ 
nia,  and  require  no  exaggeration  to  make  them  attractive.  Full  par¬ 
ticulars  in  regard  to  their  growth,  habits,  and  dimensions,  will  be 
given  in  the  botanical  volume  of  the  Geological  Report;  it  need  only 
be  added  that  the  age  of  the  tree  which  was  cut  down  in  the  Calaveras 
Grove,  and  which,  at  six  feet  above  the  ground,  has  a  diameter  of 
twenty- three  feet  inside  the  bark,  was  found  to  be  about  1300  years. 
It  was  easy  to  count  the  annual  rings,  and  they  amounted  to  1255  in 
number;  but  there  being  a  small  space,  about  a  foot  in  diameter,  at  the 
centre  of  the  tree,  from  which  the  wood  was  decayed  away,  it  would  be 
a  reasonable  estimate  to  call  the  age  of  this  particular  tree  about  1300 
years.  The  difference  in  the  rapidity  of  its  growth,  at  different  ages, 
may  be  inferred  from  the  fact  that  the  width  occupied  by  a  hundred 
rings  at  the  centre  of  the  tree  was  thirteen  inches,  and  next  to  the 
bark  was  only  three. 

The  more  time  one  spends  among  these  trees,  the  more  their  grand 
proportions  and  colossal  size  become  impressed  on  the  mind.  The 
extraordinary  dimensions  of  the  other  species  which  are  associated 
with  the  Big  Trees,  especially  of  the  Sugar  Pine — a  tree  of  which  the 
beauty  and  majesty  can  hardly  be  exaggerated — make  it  difficult  to  real¬ 
ize  that  these  are  really  so  large  as  exact  measurements  prove  them  to 
be.  Could  one  of  them  be  suddenly  transported  to  Washington  and 
placed  beside  the  Capitol,  its  summit  towering  far  above  the  statue 
which  surmounts  the  dome  of  that  noble  structure,  the  effect  produced 
would  be  overwhelming. 


THE  HEAD  OF  THE  MOKELUMNE  RIVER. 


445 


The  rocks  about  the  Calaveras  Grove  are  granitic,  overlain  with  masses 
of  volcanic  strata  in  places,  especially  towards  the  north  end  of  the 
sheltered  valley  in  which  the  trees  are  inclosed.  From  the  Big  Trees 
to  Silver  Valley,  a  distance  of  about  twenty-two  miles,  the  road  keeps 
on  the  granite,  with  a  gentle  ascending  grade,  there  being  no  change 
in  the  aspect  of  the  country,  except  such  as  is  due  to  the  rise  in  eleva¬ 
tion  affecting  the  character  of  the  forests.  At  Silver  Valley  we  have 
risen  to  7323  feet  above  the  sea-level,  having  had  on  the  south  side  of 
the  road  frequent  glimpses  of  a  region  of  granite  capped  with  volcanic 
tables,  extending  to  the  south  of  the  Stanislaus,  our  road  having  been 
along  the  north  side  of  that  river  and  at  a  distance  of  three  or  four 
miles  from  it. 

At  Silver  Valley  we  first  see  evidences  of  glacial  action,  the  rocks 
being  polished  and  grooved,  wherever  the  surface  has  not  been  exposed 
and  the  markings  become  obliterated  by  the  weather.  In  this  vicinity 
we  meet  also  with  heavy  masses  of  volcanic  materials  resting  on  the 
granite.  A  steep  hill,  at  least  a  thousand  feet  high,  two  or  three  miles 
south,  was  ascended  and  found  to  be  made  up  exclusively  of  rudely- 
stratified  ashes  and  breccia.  This  forms  an  isolated  mass,  entirely 
surrounded  by  granite,  and  all  the  prominent  points  in  the  vicinity  are 
capped  with  the  same  kind  of  volcanic  ejections,  chiefly  a  very  coarse 
conglomerate  of  angular  fragments  of  every  variety  of  lava,  cemented 
by  a  material  of  the  same  kind,  only  more  finely  comminuted. 

Between  Silver  Valley  and  the  Stanislaus  Meadows  a  ridge  is  crossed, . 
having  an  elevation  of  8089  feet,  and  another  one  8216  feet  high,  be¬ 
tween  the  meadows  and  Hermit  Valley  (also  called  Holden’s  or  Ritch- 
ie’s  Station).  Here  the  Mokelumne  River  is  struck.  The  rock  is 
granite,  capped  with  a  volcanic  breccia,  excepting  on  the  ridge  crossed 
just  before  reaching  the  river,  where  there  is  a  narrow  belt  of  metamor- 
phic  slate,  hardly  more  than  a  hundred  yards  wide.  These  slates  are 
highly  altered  and  much  contorted,  portions  of  the  mass  dipping  to  the 
northeast,  and  other  portions  in  the  opposite  direction.  They  are  also 
intersected  by  veins  of  granite,  varying  from  a  few  inches  to  several 
rods  in  thickness.  These  slates  are  very  hard,  and  exhibit  Very  dis¬ 
tinct  marks  of  former  glacial  action.  Being  of  a  very  dark  color,  they 
have  all  been  located  as'“  silver  leads.” 


44G 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


Hermit  Valley  is  7259  feet  above  the  sea-level  according  to  our  mea¬ 
surements,  and  the  snow  is  said  to  accumulate  here  in  the  winter  to  a 
very  great  depth,  owing  to  its  great  elevation  and  sheltered  position 
with  high  mountains  on  all  sides.  The  road  forks  at  this  point,  the 
old  emigrant  road,  by  way  of  the  Big  Trees  to  Carson  Valley,  going  off 
to  the  north  across  the  “  Old  Carson  Pass”  into  Hope  Valley;  the  other 
road  leads  over  to  Silver  Mountain.  In  1863  this  was  a  simple  trail, 
and  it  crossed  by  the  route  designated  on  Britton  &  Bey’s  map  as 
“  Ebbett’s  Pass;”  this  name  is,  however,  one  no  longer  known  in  that 
region,  as  we  could  find  no  one  who  had  ever  heard  of  it.  In  1863  a 
new  wagon-road  was  building,  by  a  different  route,  following  up  the 
Mokelumne  a  short  distance,  and  then  striking  across  the  water-shed 
between  that  river  and  a  branch  of  the  east  fork  of  the  Carson,  a  little 
to  the  east  of  the  old  trail.  The  new  pass  was  stated,  by  the  engineers 
of  the  road,  to  be  1656  feet  above  Hermit  Valley;  this  would  make  its 
elevation  above  the  sea  8915  feet,  while  the  summit  of  Ebbett’s  (?)  Pass, 
on  the  old  trail,  was  found  to  be  8793  feet  above  the  sea-level. 

The  crest,  along  this  portion  of  the  Sierra,  is  of  volcanic  rock,  chiefiy 
a  very  coarse  breccia;  but  the  lower  ridges  and  the  valleys,  as  well  as 
the  numerous  flats,  which  are  scattered  over  this  region,  show  the 
granitic  substructure  of  the  mountains.  The  scenery  near  the  summit 
of  the  pass  is  exceedingly  grand;  nowhere  in  the  Sierra  have  we  seen  the 
volcanic  ridges  assuming  a  more  picturesque  appearance.  The  amount 
.  of  denudation  has  been  very  great,  and  the  masses  of  rock  present  a 
constant  succession  of  sharp  pinnacles  and  fantastic  serrated  forms, 
producing  an  effect  hardly  inferior  to  anything  seen  in  the  mountains 
of  California.  Plate  9  is  an  attempt  to  reproduce  one  of  the  most  strik¬ 
ing  of  these  views.  The  point  from  which  it  was  taken  is  near  the 
summit  of  the  road  to  Silver  Mountain,  where  two  of  these  volcanic 
overflows  are  seen,  one  directly  behind,  but  towering  far  above,  the 
other.  The  sketch  was  taken  looking  towards  the  west,  near  the 
time  of  sunset,  and  the  serrated  mass  in  the  background,  rendered 
somewhat  indistinct  by  the  hazy  atmosphere  and  diffused  light  of  the 
sun  just  sinking  behind  it,  had  the  effect  of  a  reflection  of  the  lower 
ridge  in  the  sky,  or  of  a  kind  of  mirage,  which  curious  deception 
was  aided  by  the  accidental  resemblance  in  the  outlines  of  the  two 


VOLCANIC  RIDGES  NEAR  SILVER  MOUNTAIN. 


PLATE  IX,  p.  446. 


LIBRARY 
OF  THE 

UNIVERSITY  OF  ILLINOIS 


THE  HEAD  OF  THE  MOKELUMNE  RIYER. 


447 


Fig.  76. 


LAVA  ON  GRANITE. 


ridges,  and  the  very  dark  color  of  the  one  in  the  foreground.  In  the 
wood-cut,  an  attempt  lias  been  made  to  give  this  effect  of  light  and 
shade,  hut  there  is  no  exaggeration  of  the  serrated  and  pinnacled  forms 
of  the  masses  of  rock. 

Hear  the  summit  of  the  pass  there  is  an  excellent  opportunity  for 
examining  the  relations  of  the  lava  to  the  granitic  rocks.  At  one 
point  a  little  east  of  the  line  of  the  new  road,  on  the  very  crest  of  the 
ridge,  the  basaltic  massea  are  seen  resting  on  the  granite  in  the  manner 
illustrated  in  the  annexed  wood-cut  (Fig.  76),  which  represents  a  sec¬ 
tion  of  a  ridge  about  300  feet  high, 
on  the  north  side  of  which  the  beds 
of  lava  rest,  with  a  steep  inclination 
away  from  the  underlying  granitic 
mass,  and  a  heavy  accumulation  of 
fragments  of  volcanic  rock  on  the 
opposite  side.  The  granite  is  seen  to 
be  very  much  altered  in  character  for 
a  considerable  distance  from  the  lava; 
it  is  both  softened  and  reddened,  and 

has  a  concentric  structure  developed  in  it,  as  indicated  in  the  figure. 
Perched  on  the  summit  of  the  lava  are  a  few  very  large  blocks  of 
granite,  evidently  carried  there  by  glaciers,  and  one  of  the  many  indi¬ 
cations  of  the  immense  thickness  of  the  ice  in  former  times,  and  a 
striking  proof  of  the  wonderful  changes  which  have  been  wrought  in 
the  outline  of  the  surface,  within  a  recent  period  (speaking  geologically), 
by  denudation. 

A  little  below  the  summit  of  the  pass,  on  the  old  trail,  there  is  a  very 
well-marked  cone  rising  to  the  height  of  about  800  feet,  and  entirely 
surrounded  by  granite.  One  side  of  it  is  broken  away,  as  represented 
in  the  annexed  wood-cut  (Fig.  77),  which  is  from  a  sketch  taken  high 
up  on  the  side  of  Silver  Mountain,  a  grand  range  of  volcanic  materials 
forming  the  background.  This  cone,  as  seen  from  the  west,  in  descend¬ 
ing  on  the  trail  to  Silver  Mountain  town,  appears  to  be  made  up  of  a 
dark  basaltic  lava,  in  very  heavy  beds,  inclining  at  an  angle  of  about 
30°  in  all  directions  from  the  centre.  It  is  a  picturesque  and  interest¬ 
ing  locality,  as  it  is  not  often  that  we  are  able  to  see  so  clearly  that  the 


448 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


volcanic  material  must  have  been  erupted  through  a  hole  in  the  gran¬ 
ite,  which  rock  here  surrounds  the  cone,  on  all  sides,  with  a  smooth 


Fig.  77. 


VOLCANIC  CONE  AND  RIDGE  NEAR  SILVER  MOUNTAIN. 


and  unbroken  surface.  Indeed,  there  is  hardly  any  part  of  the  Sierra 
where  the  eruptive  rocks  may  be  studied  to  so  great  advantage  as  in 
the  vicinity  of  Silver  Mountain. 

The  traces  of  ancient  glaciers  become  very  abundant  as  we  descend 
from  the  summit  on  the  east  side,  until  we  come  within  about  two 
miles  of  the  town,  when  we  strike  the  volcanic  rocks  in  the  canon.  * 
But  we  noticed  in  many  places  blocks  of  granite  perched  high  up  on 
the  slopes  of  volcanic  materials,  in  positions  which  they  could  hardly 
have  attained  without  the  aid  of  ice. 

The  town  of  Silver  Mountain  lies  at  the  foot  of  the  lofty  peak  of  the 
same  name,  and  on  a  branch  of  the  east  fork  of  the  Carson.  It  is  6516 


feet  above  the  sea,  and  the  summit  of  the  mountain  is  4418  higher,  or 
10,934  feet  above  tide.  This  peak  is  higher  than  any  one  to  the  north, 
until  we  reach  Mount  Shasta,  having  an  elevation  nearly  400  feet 
greater  than  that  of  Wood’s  Peak,  which  is  the  next  high  point  in  that 
direction.  The  view  from  the  summit  is  very  line,  commanding  the 
Sierra  in  all  directions,  and  extending  over  the  wide  area,  covered  by 
volcanic  ridges,  which  lies  between  the  head-waters  of  the  Carson  and 


T1IE  HEAD  OF  THE  MOKELUMNE  RIVER. 


449 


Walker’s  Rivers.  Some  points  seen  in  this  direction  are  as  high  as 
Silver  Mountain  itself,  and  the  aspect  of  the  country  is  extremely  for¬ 
bidding  from  its  roughness  and  dryness. 

The  mass  of  Silver  Mountain  is  made  up  ot  volcanic  materials,  with 
a  great  variety  of  structure  and  composition,  and  which  we  have  had 
no  opportunity  to  examine  with  care.  There  is  perhaps  no  locality  in 
the  State  where  so  great  a  number  of  different  kinds  of  lava  might  be 
collected,  within  the  same  area,  as  in  this  vicinity.  Light-colored  tra¬ 
chytes,  dark  basalts,  and  the  curious  rhyolites,  especially  the  variety 
called  by  Richthofen  44  Nevadite,”  are  abundant.  There  are  also  at  the 
base  of  the  mountain  heavy  accumulations  of  stratified  materials, 
which  might  be  called  shales,  and  which  have  evidently  resulted  from 
the  decomposition  of  the  volcanic  rocks.  These  shales  once  occupied 
the  whole  valley  in  which  Silver  Mountain  town  is  situated,  covering  it 
to  a  depth  of  at  least  750  feet ;  but  the  larger  portion  of  the  deposit  has 
been  removed  by  denudation.  In  these  sedimentary  beds,  numerous 
remains  of  stems  and  leaves  of  plants  were  discovered. 

The  name  of  44  Silver  Mountain”  has  supplanted  the  original  one  of 
44  Ivongsberg,”  given  by  the  Norwegian  miners,  who  in  1862  com¬ 
menced  prospecting  for  silver  in  this  region.  In  1863  there  was  a 
great  excitement  in  this  vicinity,  and  many  mining  camps  were  built 
up,  several  districts  opened,  roads  constructed,  and  there  were  all  the 
external  indications  of  the  development  of  an  important  mining  region, 
excepting  such  as  could  be  gathered  from  the  examination  of  the  lodes 
themselves.  In  these,  so  far  as  the  Silver  Mountain  district  itself  is 
concerned  (not  professing  to  have  any  opinion  in  regard  to  the  adjacent 
ones,  which  we  had  no  time  to  examine),  the  indications  were  of  a  very 
discouraging  character.  A  large  number  of  specimens  were  collected 
and  assayed,  but  none  of  them  were  found  to  contain  a  workable  quan¬ 
tity  of  silver,  while  the  majority  were  entirely  destitute  of  that  or  any' 
other  valuable  metal. 

The  44  leads,”  as  they  were  called,  were  in  the  form  of  very  irregular 
masses  of  quartz,  sometimes  of  great  size,  but  never  distinctly  defined, 
so  far  as  we  could  observe.  The  metalliferous  portions  of  these  lodes 
consisted  of  very  fine  particles  of  pyrites,  with  occasionally  some 
galena,  and  here  and  there  a  little  sulphuret  of  silver,  as  was  supposed, 


GEOL.  VOL.  I. — 57 


450 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


although  the  quantity  of  this  latter  was  always  too  small  to  constitute  a 
workable  ore,  nor  can  anything  more  be  stated  with  certainty  than  that 
some  portions  of  the  rock  do  contain  traces  of  silver.  Many  claims 
were  taken  up,  where  we  could  discover  no  indications  of  ore  or  metal 
of  any  kind,  and  where  there  was  certainly  nothing  like  a  vein  or  lode. 

Before  entirely  condemning  this  region,  however,  it  should  be  visited 
again,  and  the  other  districts  lying  to  the  north  and  east  of  Silver 
Mountain  should  be  examined,  as  these  were  thought  by  some  to  pre¬ 
sent  much  more  favorable  indications  of  mineral  wealth  than  the  one 
we  have  just  noticed. 

We  here  close,  for  the  present,  our  observations  on  the  High  Sierra. 
Enough  has  been  said  in  this  chapter  to  give  an  idea  of  the  geological 
and  scenographical  character  of  this  great  range  of  mountains,  and  the 
limits  of  this  volume  forbid  our  continuing  the  description  any  farther. 
After,  or  at  the  time  of,  the  publication  of  our  map  of  Central  Califor¬ 
nia,  and  after  a  more  minute  survey  of  the  very  important  routes  across 
the  Sierra,  between  the  Big  Tree  road  and  Beckworth’s  Pass,  we  shall 
be  in  a  position  to  do  much  more  ample  justice  to  this  portion  of  the 
State,  in  our  future  volumes  of  Geology  and  Physical  Geography.  We 
pass  now,  therefore,  to  a  consideration  of  the  eastern  slope  of  the 
Sierra. 


CHAPTER  XL 

THE  EASTERN  SLOPE. 

Section  I. — Mono  Lake  and  its  Vicinity. 

Mono  Lake  lies  in  a  depression  or  basin  occupying  a  portion  of  an 
elevated  plateau  of  desert  land  situated  at  the  eastern  base  of  the 
Sierra  Xevada,  and  between  the  headwaters  of  Owen’s  and  Walker’s 
Rivers.  Some  of  the  branches  of  Owen’s  River  head  within  five 
miles  of  the  lake,  which  is  chiefly  supplied  with  water  from  the  streams 


MONO  LAKE  AND  ITS  VICINITY. 


451 


rising  in  the  Sierra  between  Mount  Dana  and  Castle  Peak,  and  they 
descend  very  rapidly,  as  between  these  two  mountains,  the  distance 
from  the  summit  of  the  range  to  the  lake-shore  is  only  about  six  miles, 
and  the  difference  of  elevation  is  over  6000  feet.  On  all  other  sides 
except  towards  the  Sierra  the  lake  is  surrounded  by  a  wide  belt  of 
desert  region,  there  being  an  area  of  perhaps  as  much  as  400  square 
miles  embraced  within  the  basin. 

Mono  Lake  is  about  fourteen  miles  long  from  east  to  west,  and  nine 
wide  from  north  to  south,  in  its  broadest  portion  ;  but  it  has  formerly 
been  much  more  extensive  than  it  now  is,  the  terraces  which  indicate  its 
ancient  shores  being  very  conspicuous.  They  may  be  traced  entirely 
round  the  lake,  although  broken  in  some  places ;  but  they  can  be  best 
measured  on  the  western  side,  where  the  hills  rise  steeply.  On  this  side 
there  is  a  very  distinct  terrace  385  feet  above  the  water,  and  the  high¬ 
est  well-detined  one  is  about  680  feet  above  the  present  surface  of  the 
lake.  On  the  northern,  eastern,  and  southeastern  sides  they  are  numer¬ 
ous,  and  stretch  back  on  the  more  gradually  sloping  ground  for  many 
miles.  The  annexed  wood-cut  (Fig.  78)  will  serve  to  give  an  idea  of 
the  appearance  of  these  terraces  as  seen  at  Black  Point  on  the  north¬ 
western  side  of  the  lake. 


Pig.  78. 


TERRACES  ON  RLACK  POINT,  MONO  LAKE. 


On  the  southeast  side,  between  the  Sierra  and  the  first  volcanic 
chain 9  an  arroyo  has  cut  through  the  sandy  desert  from  sixty  to  a  hun¬ 
dred  feet  deep,  and  along  this  in  places  live  well-marked  terraces  can 


i 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


45  2 


be  seen.  The  old  mountaineers  say,  that  at  a  former  period  the  lake 
was  high  enough  to  pass  through  a  gap  to  the  northeast,  and  connect 
with  Walker’s  Lake.  If  this  be  true,  there  must  have  been  a  sheet  of 
water  here  more  than  fifty  miles  long  from  east  to  west  ;  but  of  what  its 
form  and  extent  may  have  been  we  know  too  little  of  the  topography 
of  this  region  to  give  any  clear  idea.  As  the  level  of  the  water  was 
once  certainly  more  than  600  feet  above  its  present  stage,  this  great 
interior  lake  may  have  connected  with  the  valleys  of  the  Carson  and 
Humboldt,  and  have  formed  a  more  conspicuous  feature  in  the  geo¬ 
graphy  of  the  country  than  the  present  “  Great  Salt  Lake”  does. 
Whatever  cause  gave  rise  to  the  immense  body  of  ice,  in  the  form  of 
glaciers,  which,  as  we  have  seen,  formerly  covered  the  summit  of  the 
Sierra  in  this  region  and  extended  down  for  5000  feet  or  more  from  the 
crest,  this  would  undoubtedly  have  been  sufficient  to  supply  water 
enough  to  raise  the  lake  to  the  height  which  the  terraces  about  it  show 


that  it  must  office  have  had. 

The  water  of  the  lake  is  of  a  high  specific  gravity  and  intensely 
saline.  It  has  not  yet  been  accurately  analyzed.  It  undoubtedly  con¬ 
tains  a  large  amount  of  common  salt  and  of  carbonate  of  soda,  as  it 
removes  grease  and  washes  as  well,  or  better,  than  soap-suds.  Its  sur¬ 
face  is  not  easily  thrown  into  waves,  but  is  generally  smooth  and 
glassy;  from  a  distance,  it  has  an  oily  appearance.  It  contains  some 
biborate  of  soda  (borax),  but  the  amount  has  not  been  determined.  It 
also  holds  considerable  lime  in  solution,  as  is  evident  from  the  fact 
that  large  quantities  of  calcareous  tufa  have  been  deposited  along 
the  shore  and  on  the  terraces  far  above  the  present  level  of  the  water; 
it  is  this  tufa  which  has  been  repeatedly  mistaken  for  coral,  and  has 
thus  given  rise  to  a  belief  that  the  lake  must  in  former  times  have 
had  some  connection  with  the  sea.  Hear  the  north  shore  there  are 
springs,  holding  much  lime  in  solution,  which  have  made  extensive 
deposits  of  tufa  in  the  lake,  some  of  which  rise  in  fantastic  shapes  like 
pillars,  or  gigantic  fungi,  from  six  to  ten  feet  above  the  water ;  these 
springs  are  less  copious  than  they  formerly  were.  There  are  also 
extensive  springs  of  fresh  water,  which  rise  in  the  lake  near  its  western 
shore,  fed  from  the  mountains  on  that  side. 

There  are  several  islands  in  Mono  Lake,  two  of  which  are  of  con- 


MONO  LAKE  AND  ITS  VICINITY. 


453 


siderable  size,  the  largest  being  two  and  a  half  miles  long  from  north 
to  south,  and  the  other  about  half  a  mile  in  length  from  east  to  west. 
To  the  north  of  this  lies  a  group  of  islets.  These  are  all  composed  of 
volcanic  materials.  The  largest  one  is  chiefly  made  up  of  ashes,  or 
loose  eruptive  masses,  portions  of  which  are  stratified,  and  appear  to 
have  been  deposited  under  water.  The  softer  strata  have  been,  in 
places,  broken  and  contorted  since  their  deposition,  and  there  is  every 
indication  that  the  volcanic  action  has  ceased  at  a  very  recent  period,  or, 
rather,  that  it  has  not  yet  fully  died  out.  On  the  southeast  corner  of 
the  larger  island  are  extensive  hot  springs  and  steam  jets,  covering  per¬ 
haps  thirty  acres  of  land  and  extending  into  the  lake.  This  portion  of 
the  island  is  of  hard  black  basalt,  with  some  scoriae  and  cinders,  which 
materials  form  the  eastern  end  of  the  island,  the  western  side  being 
made  up  of  stratified  ashes,  more  or  less  indurated.  The  steam  and 
hot  gases  escape  from  hundreds  of  vents,  and  often  with  considerable 
noise.  About  the  orifices  of  many  of  these  fumaroles  there  are  thin 
red  incrustations  which  appear  to  consist  of  chloride  of  iron.  There  is 
but  little  smell  of  sulphur  and  no  deposit  of  this  material.  Some  of 
these  springs  furnish  a  copious  supply  of  boiling  water,  and  large  quan¬ 
tities  of  it  come  out  at  the  edge  of  the  lake,  raising  its  temperature 
very  perceptibly  for  many  rods  from  the  shore.  In  one  place  a  large 
fissure  occurs,  caused  by  the  falling  in  of  a  portion  of  the  crust,  and 
this  must  have  taken  place  at  quite  a  recent  period,  since  the  bushes 
which  grew  on  the  sunken  portion  are  still  to  be  seen  in  the  rubbish 
at  the  bottom.  Much  steam  and  hot  gases  issue  from  this  cavity. 
There  are  two  well-defined  craters,  now  filled  with  water,  on  the  north¬ 
eastern  part  of  the  island,  in  the  midst  of  the  hard,  black  basalt. 

The  second  island  in  size  is  entirely  of  hard  basaltic  rock,  and  has 
at  its  western  end  a  well-defined  volcanic  cone,  of  black  basalt  and  cin¬ 
ders.  This  cone  is  about  300  feet  high,  and  is  very  rough  and  entirely 
destitute  of  vegetation ;  it  appears  to  be  more  recent  than  any  cone 
seen  in  this  State,  unless  it  be  those  to  the  north  of  Lassen’s  Peak. 

My  riads  of  gulls  and  other  aquatic  birds  resort  to  this  lake  to  breed 
during  the  summer;  but  the  water  is  destitute  of  life,  excepting  a  small 
fly,  of  which  the  larva  is  a  white  worm,  which  occurs  in  immense 


454 


GEOLOGY  OF  THE  SIERRA  NEVADA 


quantities,  and  which,  when  dried,  furnishes  an  important  article  of  food 
to  the  Indians  of  this  region,  and  is  called  by  them  “  Koo-ehah-bee.” 

Stretching  south  from  Mono  Lake,  in  a  north  and  south  direction,  is 
a  chain  of  extinct  volcanoes,  having  a  remarkable  appearance  as  seen 
from  the  west  or  north,  as  illustrated  by  the  annexed  wood-cut  (Fig. 
79).  It  is  a  cluster  of  truncated  cones,  with  very  steep  sides,  chief  y 


Fig.  79. 


VOLCANIC  CONES  NEAR  MONO  LAKE. 


covered  with  ashes  and  other  loose  materials,  and  having  numeious 
rocky  projections  rising  from  their  broadly  truncated  tops.  The  high¬ 
est  of  these  was  ascended,  and  its  sides  found  to  be  covered  with  loose 
ashes,  lying  at  as  steep  an  angle  as  the  material  would  allow,  mixed 
with  fragments  of  volcanic  rock  of  various  kinds,  especially  of  trachyte. 
The  broad  top  was  found  to  be  of  a  light-gray  trachyte,  with  about 
twelve  sharp  knobs  rising  around  the  outside,  apparently  the  remains 
of  the  lip  of  the  ancient  crater.  Obsidian  and  pumice  are  abundant  on 
the  top  and  sides  of  the  cone  and  over  the  plain  beneath.  The  soil  oi 
ashes  of  all  these  cones  is  intensely  dry  and  pulverulent,  so  that  a  man 
sinks  into  it,  at  every  step,  over  the  ankles,  yet  it  supports  in  places  a 
stinted  growth  of  trees  and  shrubs,  and  even  of  herbaceous  plants.  It 
is  evident  that  but  little  rain  ever  falls  here,  as  the  sides  of  these  cones 
are  so  little  washed,  the  material  ot  which  they  are  composed  being  of 


owen’s  valley. 


455 


such  a  character  that  they  could  not  long  retain  their  present  form,  ex¬ 
cept  in  a  very  dry  climate. 

These  cones  rise  to  the  height  of  from  9200  to  9300  feet  above  the 
sea-level,  and  the  highest  is  about  2750  feet  above  the  level  of  Mono 
Lake.  Ths  belt  of  volcanic  rock  stretches  to  the  south,  and  appears 
to  enter  the  Sierra  and  to  extend  entirely  to  the  summit,  the  crest  being 
there  considerably  lower,  as  if  from  the  denudation  of  the  softer  volcanic 
materials.  From  the  summit  of  the  cone  ascended,  a  similar  volcanic 
range  was  seen  about  twenty-five  miles  farther  to  the  east,  apparently 
parallel  with  the  one  examined.  In  fact,  all  through  this  region,  be¬ 
tween  the  heads  of  Walker’s  and  Owen’s  Rivers,  the  volcanic  forma¬ 
tions  predominate. 

At  the  summit  and  within  the  crater  of  the  cone  ascended,  several 
boulders  of  rose-colored  granite  were  observed  mixed  with  the  volcanic 
ashes,  pumice  and  other  erupted  materials.  Their  origin  is  a  curious 
problem,  as  it  is  difficult  to  suppose  that  any  flow  of  water  or  mass  of 
glacier-ice  could  ever  have  reached  anything  like  this  height  above  the 
valley.  Indeed,  had  there  been  such,  the  cones  of  this  region  could 
hardly,  by  any  possibility,  have  retained  their  peculiarly  regular  out¬ 
line  ;  they  would  certainly  have  exhibited  marks  of  subaqueous  erosion. 
The  most  plausible  supposition  in  regard  to  these  boulders  is,  that  they 
were  ejected  from  the  craters  by  the  same  force  which  brought  the 
other  materials  of  which  the  cones  are  composed  to  the  surface.  They 
must,  in  this  case,  have  been  torn  off*  from  the  underlying  granite 
through  which  the  eruptive  matter  has  forced  its  way,  as  is  seen  every¬ 
where  in  the  Sierra. 


Section  II. — Owen’s  Valley. 

Owen’s  Valley  is  a  narrow  basin  between  extremely  lofty  mountains; 
it  is  about  140  miles  in  length  north  and  south,  and  its  average  width 
is  about  ten  miles.  Along  its  western  edge  it  is  bordered  by  the 
Sierra  Nevada,  which  presents  an  almost  unbroken  wall  in  this  part  of 
its  course,  rising  in  its  highest  peaks,  which  are  just  opposite  Owen’s 
Lake,  to  15,000  feet,  and  having  no  pass  across  it  of  less  than  11,000 


456 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


feet  in  elevation.  Opposite  Owen’s  Lake  the  descent  from  the  summit 
of  the  Sierra  to  the  valley  must  average  fully  1000  feet  per  mile,  the 
distance  being  ten  or  eleven  miles,  and  the  difference  of  level  in  that 
part  of  the  range  between  the  highest  points  and  the  valley  being  from 
10,500  to  11,000  feet.  This  would  seem  to  be  one  of  the  steepest 
mountain  profiles  in  the  country. 

This  portion  of  the  Sierra,  as  seen  from  the  valley,  is  peculiarly 
grand;  the  steep  slopes  rise  from  the  desert  plain,  and  are  everywhere 
naked  and  destitute  of  forests,  the  only  trees  being  the  pines  in  the 
canons,  and  the  scattered  nut-pines,  which  are  scrubby  and  small,  and 
extend  up  to  about  8000  or  9000  feet,  the  rest  of  the  ridges  being  made 
up  of  patches  of  bare  soil,  with  exceedingly  steep  slopes  of  naked  gray 
rock  or  snow.  From  this  side  the  mountains  look  desolate,  forbidding, 
and  immensely  high,  so  much  so  that  it  is  a  wonder  it  had  never  been 
surmised  that  this  was  the  most  elevated  portion  of  the  Sierra,  until 
the  visit  of  the  Geological  Survey  to  this  region  in  1864. 

On  the  eastern  side  of  the  valley  the  mountains  are  more  broken, 
but  almost  as  high  and  grand  as  those  on  the  western,  and  apparently 
forming  one  continuous  range,  as  far  as  known  from  any  topographical 
information  yet  published ;  but  it  must  be  remembered  that,  up  to 
this  time,  there  has  never  been  any  instrumental  exploration  made  of 
the  region  in  question,  and  so  barren  and  forbidding  is  it,  that  it  is 
hardly  possible  to  look  forward  to  a  time  when  the  country  between 
Owen’s  Valley  and  the  Colorado  will  be  known  in  anything  more  than 
the  rudest  outlines  of  its  topography  and  geology.  It  is,  beyond  a 
doubt,  the  most  difficult  region  to  explore  within  our  territory.  At 
present  it  is  reserved  by  the  Indians  as  a  sort  of  stronghold,  or  last 
resort.  The  range  on  the  eastern  side  of  Owen’s  Valley  is  called  the 
Inyo  Mountains  towards  the  south  end,  and  the  White  Mountains  far¬ 
ther  north  ;  but  there  does  not  appear  to  be  any  especial  reason  for 
thus  dividing  the  chain,  as  it  is  a  continuous  one. 

These  mountains  are  very  dry  and  desert-like,  not  a  single  stream 
of  any  size  flowing  from  them  into  Owen’s  Valley,  which  is  exclusively 
supplied  with  water  by  the  melting  of  the  snow  stored  away  during 
the  winter  on  the  upper  part  of  the  eastern  slope  of  the  Sierra.  The 
quantity  of  rain  which  falls  in  the  valley  must  be  exceedingly  small  at 


0  AV  E  N  ’  S  VALL  E  Y. 


457 


all  times,  and  during  the  years  1863  and  1864  it  was,  as  reported, 
almost  null.  The  White  and  Inyo  Mountains  are  destitute  of  forest 
vegetation,  excepting  a  few  scattering,  scrubby  pines,  mostly  the  nut- 
pine,  or  Finns  Fremontiana. 

Owen’s  River  rises  in  the  Sierra  Nevada,  not  far  from  the  head  of 
the  San  Joaquin,  and  near  the  south  end  of  the  valley  sinks  in  the  lake 
of  the  same  name,  which  is  about  twenty  miles  long.  The  tributaries 
which  this  river  receives  from  the  Sierra  are  small  streams;  but  these 
will  be  of  the  greatest  importance  to  the  settlers,  when  used  for  the 
purposes  of  irrigation,  as  they  must  be  in  case  the  mines  become  per¬ 
manently  valuable.  These  streams,  as  they  issue  from  the  mountain 
canons,  flow  out  upon  great  piles  of  detritus,  or  “  washes,”  consisting 
of  coarse  and  fine  debris  brought  by  the  stream  from  the  mountains 
and  piled  up  on  the  plain  with  a  gradual  slope  into  the  valley.  This 
slope  of  detritus  extends  along  the  whole  base  of  the  mountains,  but  is 
highest  where  the  streams  come  out,  so  that  the  latter  often  separate 
into  several  branches,  as  they  flow  down  it,  thus  making  irrigation 
quite  easy,  and  giving  rise  to  a  considerable  expanse  of  meadow  along 
the  various  channels. 

Our  party,  under  the  charge  of  Professor  Brewer,  passed  hastily  up 
the  valley  in  July,  1864,  having  crossed  the  Sierra  by  the  King’s  River 
Pass,  in  order  to  get  north,  so  as  to  reach  the  head  of  the  San  Joaquin 
River  by  recrossing  the  mountains.  The  weather  was  intensely  hot, 
the  thermometer  standing  all  the  time  at  from  100°  to  104°  in  the 
shade,  and  the  party  suffered  the  more,  as  they  had  been  long  enough 
among  the  snows  of  the  High  Sierra  to  have  become  almost  acclimated 
there. 

The  first  day’s  ride  was  to  the  Black  Rocks,  twenty-two  miles,  the 
road  passing  along  on  the  west  side  of  the  river,  over  the  desert  slope ; 
but  grass  is  abundant  along  the  river,  and  where  the  streams  come 
down  from  the  Sierra;  even  the  desert,  when  irrigated,  as  near  Fort 
Independence,  produces  well.  Except  in  the  vicinity  of  the  volcanic 
rocks,  all  the  boulders  seen  in  the  valley  were  of  granite.  The  Black 
Rocks  form  a  table  of  lava,  descending  from  the  Sierra  by  a  compar¬ 
atively  gentle  slope,  very  rough  and  uneven  in  its  details;  but,  as 
seen  from  a  distance  so  that  the  minor  irregularities  disappear,  it 


GEOL.  VOL.  I. — 58 


458 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


appears  as  regular  and  uniform  in  its  descent  as  a  great  wash  or  em¬ 
bankment  of  gravel.  This  mass  of  lava  lies  nearly  opposite  to  the 
Palisades,  a  ridge  of  volcanic  materials  which  forms  the  crest  of  the 
Sierra,  as  noticed  in  the  description  of  this  part  of  the  mountains.  The 
lava  of  the  Black  Rocks  seems  to  have  issued  from  the  granite  at  a 
point  about  half  way  up  the  slope  of  the  mountains,  or  at  an  altitude 
of  8000  or  9000  feet.  A  similar  stream  came  from  the  other  side  of 
the  valley,  from  the  Inyo  Mountains,  so  that  the  two  nearly  meet 
together,  leaving  only  a  narrow  strip  of  bottom-land  between.  From 
beneath  the  lava,  on  the  west  side  of  the  river,  issue  copious  springs  of 
clear  fresh  water,  of  which  the  largest  is  known  as  Fish  Springs ;  this 
forms  a  stream  several  feet  deep  and  ten  or  twelve  yards  wide.  Sev¬ 
eral  others  of  the  same  character  were  seen,  and  they  resemble  those 
which  are  described  in  another  part  of  this  volume  as  occurring  in  the 
northern  part  of  the  State.  They  originate  in  the  same  way,  namely, 
by  the  water,  derived  from  the  melting  of  the  snow  high  up  in  the 
mountains,  finding  its  way  under  the  lava,  running  thus  for  miles,  and 
finally  issuing  from  it  at  its  base.  The  lava  of  this  stream  is  of  that 
hard,  dark-colored,  basaltic  variety  so  common  in  the  northern  part  of 
the  chain.  The  width  of  the  volcanic  mass,  on  the  west  side  of  the 
valley,  is  about  fifteen  miles ;  on  the  other,  it  is  about  two-thirds  as 
much.  All  through  here,  the  Sierra  is  of  granite  entirely  down  to  the 
edge  of  the  lava. 

The  Warm  Springs,  Camp  185,  issue  from  syenitic  granite  at  the 
base  of  the  Sierra,  and  are  quite  copious;  there  are  several  of  these 
close  together,  which  unite  to  form  one  stream.  The  water  seemed 
pure,  and  had  a  temperature  of  122°  to  125°. 

From  the  Warm  Springs  to  Round  Valley,  the  road  leads,  for  most 
of  the  way,  over  a  desert  plain,  the  boulders  brought  down  from  the 
Sierra  showing  the  slopes  of  the  mountains  to  be  made  up  of  granite 
and  lava,  the  former  predominating,  and  often  much  reddened  and 
altered  by  contact  with  the  volcanic  rocks.  At  Bishop’s  Creek  the  val¬ 
ley  between  the  Sierra  and  the  White  Mountains  widens  considerably 
to  the  north,  and  is  entirely  occupied  by  a  table  of  lava,  excepting  a 
nook  or  circular  area  which  lies  between  it  and  the  Sierra,  and  which 
is  called  Round  Valley.  This  mass  of  lava  is  highest  along  its  centre, 


owen’s  valley. 


459 


forming  at  its  sides,  as  it  were,  two  broad  valleys.  The  eastern  one  of 
these  is  dry,  as  no  streams  come  down  from  the  mountains  on  that  side, 
and  it  is  said  to  he  alkaline  and  desert,  the  road  to  Mono  Lake  and 
Aurora  passing  through  it  on  its  eastern  edge;  the  distance  to  Aurora 
from  Hound  Valley  is  called  sixty-five  miles. 

Owen’s  River  flows  down  on  the  western  side  of  this  lava  table,  and 
in  places  has  excavated  in  it  a  canon  a  hundred  feet  or  more  deep. 
Through  here  the  meadows  were  finer  than  any  seen  in  the  State,  the 
grass  being  as  high  as  the  horses’  hacks,  and  the  whole  being  easily 
kept  irrigated  by  the  streams  from  the  Sierra. 

But  little  is  known  of  the  geology  of  the  ranges  bordering  Owen’s 
Valley  on  the  east  side.  From  Bend  City,  for  twenty-five  miles  north, 
their  western  base  and  slope  seem  to  he  made  of  slate  and  other  strati¬ 
fied  rocks,  generally  dipping  to  the  southwest,  and  often  much  con¬ 
torted.  These  slates  are  said  to  alternate  with  beds  of  limestone.  A 
single  fossil  was  found  in  these  rocks,  opposite  Camp  Independence, 
by  Dr.  Horn;  it  was  a  species  of  Goniatite  ( Goniatites  Icevidorsatus , 
Hauer),  identical  with  one  found  by  us  in  El  Dorado  Canon,  near  Day- 
ton,  in  Nevada,  and  which  undoubtedly  belongs  to  the  Triassic  series; 
this  is  considered  by  Mr.  Gabb  as  the  same  species  which  has  been  de¬ 
scribed  by  Hauer  as  occurring  in  the  upper  Trias  of  the  Alps.  There 
would  appear  to  be  sufficient  evidence  to  justify  our  considering  these 
strata  along  the  western  flanks  of  the  Inyo  and  White  Mountains  as 
identical  with  the  rocks  of  Washoe,  which  certainly  occupy  a  geologi¬ 
cal  position  closely  allied  with  that  of  the  metalliferous  rocks  of  Owen’s 
Valley. 

It  is  said  by  explorers  that  the  central  portion  of  the  Inyo  and  White 
Mountain  range  is  of  granite,  and  that  stratified  rocks  occur  on  its  east¬ 
ern  flank,  which  dip  to  the  east,  forming  an  anticlinal  axis.  In  some 
places,  the  crest  of  this  chain  is  very  rough  in  outline,  and  rises  in  nu¬ 
merous  pinnacles.  One,  like  a  pillar,  on  the  very  summit  of  the  range,  is 
called  the  “  Pah  Ute  Monument ;”  it  is  conspicuous  for  a  great  distance, 
and  is  a  noted  landmark.  It  is  also  stated  that  there  are  several 
ranges  east  of  this,  in  close  proximity  to  each  other,  with  narrow  strips 
of  desert  valley  between,  some  portions  of  which  are  covered  with 
deposits  of  salt.  In  1864,  there  was  some  excitement  in  regard  to  the 


/ 


460 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


alleged  discovery  of  a  bed  of  pure  rock-salt,  several  feet  thick,  in  the 
second  valley  east  of  Bend  City.  The  range  east  of  San  Carlos  was 
estimated  at  about  10,000  feet  in  height,  and  it  appears  to  maintain  an 
elevation  of  as  much  as  8000  or  9000  feet  for  some  seventy  miles  to  the 
north ;  but  it  sinks  to  the  south,  beyond  Owen’s  Lake,  forming  low  and 
broken  ridges  in  that  direction,  where  it  unites  with  the  Coso  Moun¬ 
tains.  About  seventy  or  eighty  miles  north  of  San  Carlos,  there  is  a  high 
peak  called  the  “  White  Mountain,”  which  is  doubtless  14,000  feet  or 
more  in  elevation,  as  it  has  large  patches  of  snow  on  its  southern  side, 
and  it  was  said  by  the  miners  that  this  snow  never  entirely  disappears. 
This  peak  was  levelled  to  by  Mr.  King  from  the  summit  of  Mount 
Tyndall,  and  it  was  thought  by  him  that  it  was  probably  about  14,600 
feet  high,  and  possibly  higher  than  any  peak  in  the  Sierra.*  It  was 
also  very  conspicuous  from  Mount  Dana,  opposite  Mono  Lake. 

Deep  Spring  Valley  has  been  described  to  us,  by  Mr.  J.  E.  Clayton, 
as  a  remarkable  crater-like  depression,  high  up  on  the  flanks  of  the 
White  Mountain  range,  with  very  steep  sides,  the  crest  being  covered 
with  a  dense  growth  of  pinon  pines.  Mr.  Clayton  also  notices  the 
occurrence  of  heavy  masses  of  volcanic  material  along  the  summit  of 
this  range,  which  would  correspond  with  what  is  observed  farther 
north  on  what  appears  to  be  its  continuation. 

Explorers  have  been  actively  engaged  for  some  time  along  the  flanks 
of  the  Inyo  and  White  Mountain  range,  and  many  mineral-bearing 
lodes  have  been  discovered,  of  which  attractive-looking  specimens  have 
been  brought  to  San  Francisco.  Ko  detailed  examination  of  this  re- 
gion  has  yet  been  made  by  the  Survey,  and  we  are  unable,  therefore, 
to  give  any  opinion  as  to  its  probable  value.  Troubles  with  the  Indians 
have,  hitherto,  made  it  difficult  for  our  small  party  to  explore  the 
vicinity  of  Owen’s  Valley;  but  it  is  evidently  a  very  interesting  part  of 
the  State,  and  we  shall  not  fail  to  turn  our  attention  in  this  direction  as 
soon  as  it  is  in  our  power  to  do  so. 


*  See  page  387. 


THE  GREAT  BASIN. 


4G1 


Section  III. — The  Great  Basin. 

A  vast  region  of  desert  and  mountain  extends  over  the  southeast¬ 
ern  portion  of  California.  It  comprises  all  that  region  lying  to  the 
northeast  of  the  San  Gabriel,  San  Bernardino,  and  San  Jacinto  Moun¬ 
tains,  and  extending  to  the  Colorado  River,  which  forms  the  southeast¬ 
ern  boundary  of  the  State,  while  it  is  limited  on  the  northwest  by  the 
range  of  the  Sierra  Nevada,  as  it  curves  round  to  meet  the  Coast 
Ranges.  This  region  is  in  intimate  connection  with  the  Great  Basin, 
or  the  region  lying  chiefly  in  Nevada  and  Utah  which  has  no  drainage 
into  the  sea.  This  Great  Basin,  however,  is  not  by  any  means  a  unity; 
it  consists,  rather,  of  a  number  of  independent  basins,  each  one  having 
a  system  of  drainage  of  its  own,  but  nowhere  collecting  the  water  in 
suflicient  quantity  to  till  up  the  reservoir,  or  to  cause  it  to  run  over 
and  seek  an  outlet  to  the  ocean.  The  Colorado  flows  as  a  large  and 
navigable  stream  along  the  borders  of  California  for  more  than  a  hun¬ 
dred  and  fifty  miles;  but  it  does  not,  in  that  distance,  receive  a  single 
tributary,  although  the  mountains  are  almost  everywhere  close  upon  the 
river  ;  the  fall  of  rain  in  this  region  is  not  suflicient  to  give  rise  to  an}^ 
stream  of  sufficient  size  not  to  lose  itself  as  soon  as  it  enters  the  plain. 

A  large  part  of  the  Great  Basin  in  California  has  been  hardly  ex¬ 
plored  at  all,  as  yet,  and  the  topography  of  the  most  of  it  is  as  little 
known  in  its  details  as  if  it  lay  in  the  heart  of  the  continent.  It  is 
true  that  this  region  is  represented  in  the  General  Land  Office  map  as 
subdivided  into  sections;  but  there  is  good  reason  to  believe  that  a 
portion,  at  least,  of  this  work  is  fraudulent  and  fictitious ;  large  sums 
were  paid  for  running  these  lines,  but  a  comparison  of  the  geograph¬ 
ical  data  in  our  possession  with  those  given  in  the  Land  Office  map 
would  indicate  very  strongly  that  there  is  more  fiction  than  reality  in 
what  is  represented  thereon. 

The  principal  materials  we  have  for  illustrating  the  geology  and 
topography  of  the  region  in  question  are  derived  from  notes  by  Dr. 
Cooper  of  a  journey  over  the  Mohave  trail  to  Fort  Mohave,  and  a 
residence  of  one  winter  at  that  post.  Besides  this,  we  have  Professor 
Brewer’s  memoranda  of  a  trip  by  himself  and  Mr.  Gabb,  along  the 
northern  edge  of  the  basin,  in  1863.  Mr.  J.  E.  Clayton  has  also  fur- 


462 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


nished  some  valuable  information  in  regard  to  the  Colorado  region, 
and  quite  a  number  of  notes  and  specimens  have  been  sent  to  the  office 
of  the  Survey  by  other  explorers.  We  have  also  examined  the  notes 
of  the  “United  States  and  California  Boundary  Commission,”  in  which 
there  is  a  brief  notice  of  a  reconnaissance,  made  in  1861,  through  the 
northern  part  of  the  California  portion  of  the  Great  Basin,  from  the 
Colorado  River,  across,  by  Death  Valley,  to  Owen’s  Valley.  The  geo¬ 
logical  portion  of  these  manuscripts  is  of  no  great  value,  but  the  topo¬ 
graphical  notes  by  Mr.  Biesta  and  the  map  by  Mr.  Van  Dorn  furnish 
some  important  information  in  regard  to  a  region  where  but  few  ex¬ 
plorers  have  penetrated. 

The  shape  of  the  Great  Basin  forming  the  southeastern  corner  of  the 
State  of  California  is  nearly  rectangular,  the  State  boundary  on  the 
east  being  about  parallel  with  the  ranges  of  mountains  which  bound  it 
on  the  west  and  separate  it  from  the  region  traversed  by  streams  flow¬ 
ing  into  the  Pacific ;  the  Colorado  on  the  southeast  is  also  approxi¬ 
mately  parallel  with  the  range  forming  the  southern  termination  of  the 
Sierra  ;  as  thus  limited,  the  district  in  question  would  be  about  215 
miles  long  from  northwest  to  southeast,  and  125  miles  broad  in  the 
opposite  direction,  making  an  area  of  not  less  than  27,000  square  miles, 
or  a  territory  three  times  as  large  as  the  State  of  Maryland,  nearly  all 
of  which  is  comprised  in  San  Bernardino  County.  The  whole  of  this 
region  may  properly  be  called  a  desert,  so  far  as  its  being  suited  for 
the  residence  of  a  civilized  population  is  concerned;  yet  it  is  not 
entirely  destitute  of  those  resources  which  can  be  made  available  for 
the  support  of  life,  when  one  is  driven  to  do  so  by  necessity,  or  by  the 
desire  of  making  money.  The  discovery  of  very  rich  and  permanent 
mines  might  lead  to  the  formation  of  large  settlements,  or  even  the 
building  up  of  towns  or  cities,  as  has  already  taken  place  in  the  adja¬ 
cent,  and  not  very  differently  situated,  region  of  Nevada.  At  present 
there  are  no  permanent  settlements  of  any  considerable  size  in  this 
part  of  the  State,  although  a  great  deal  of  exploration  and  prospecting 
lias  been  done  there.* 

*  In  regard  to  the  present  condition  of  the  mining  interestsin  the  Colorado  region,  we 
have  little  or  no  late  and  reliable  information.  We  propose  to  make  an  exploration  of 
this  part  of  the  State  during  the  coming  winter,  if  our  means  permit. 


THE  GREAT  BASIN. 


463 


The  mountains  which  border  the  region  in  question  on  the  west, 
beginning  at  the  San  Francisquito  Pass,  are  the  San  Gabriel  Range, 
the  San  Bernardino  Mountains,  the  San  Jacinto  Mountains,  and  the 
group  to  the  east  of  the  San  Diego.  The  principal  passes  which  cross 
these  ranges  are  the  Cajon  Pass,  between  the  San  Gabriel  and  San 
Bernardino  Mountains;  the  San  Gorgono,  between  the  San  Bernardino 
and  the  San  Jacinto  Ranges;  and  Warner’s  Pass,  which  leads  from  the 
plains  of  San  Bernardino,  by  a  circuitous  route,  to  the  west  of  the  San 
Jacinto  Mountains,  into  the  Colorado  Valley.  This  latter  was  for 
some  time  in  daily  use  as  a  part  of  the  Overland  Stage  route,  as  long 
as  this  continued  on  the  southern  line  from  New  Mexico  to  Fort  Yuma 
and  thence  to  Los  Angeles.  All  these  passes  were  surveyed  by  Lieu¬ 
tenant,  now  Major,  Williamson,  or  parties  under  his  charge,  and  a 
full  account  of  them  will  be  found  in  the  fifth  volume  of  the  Pacific 
Railroad  Reports.  The  Cajon  Pass  is  the  one  which  is  in  most  gen¬ 
eral  use  for  the  travel  across  the  desert  to  the  Upper  Colorado,  as  it 
leads  down  the  Mohave  River  by  the  old  Spanish  trail  to  Santa  Fe ;  and 
from  Soda  Lake,  the  sink  of  the  Mohave,  it  crosses  the  mountains  to 
Fort  Mohave,  near  the  initial  point  of  the  boundary  line,  where  the 
35th  parallel  meets  the  Colorado  River.  The  summit  of  the  Cajon  is 
given  by  Williamson  as  4676  feet  above  tide ;  the  pass  ascends  on  the 
Pacific  side  by  a  very  steep  incline,  and  descends  to  the  Mohave  by  a 
much  more  gentle  and  uniform  one. 

The  following  account  of  the  geology  and  geography  of  the  Mohave 
trail  is  chiefly  extracted  from  the  notes  of  Dr.  Cooper,  who  passed  over 
it  twice  in  the  winter  of  1860-1  : 

Leaving  the  Colorado  bottom,  the  road  passes  for  twenty  miles  over  a 
granitic  range,  the  summit  of  which  is  about  2000  feet  above  the  level 
of  the  river  at  the  point  where  the  road  crosses  it,  while  the  peaks  on 
each  side  rise  about  1000  feet  higher.  This  is  called  the  Pah  Ute  Range. 
The  rock  is  granitic,  containing  a  large  amount  of  friable  feldspar,  and 
is  intersected  by  metalliferous  veins.  The  slopes  are  very  gradual  and 
the  surface  mostly  smooth,  covered  with  fragments  of  granite  forming 
a  coarse  gravel ;  but  points  and  ridges  of  rock  are  left  standing  here 
and  there,  and  are  very  rough  and  precipitous.  The  valley  between 
this  summit  and  the  next  is  shallow  where  the  road  crosses  it,  its  bot- 


4G4 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


tom  being-  marked  by  a  dry,  sandy  arroyo,  through  which  the  moun¬ 
tain  torrents  run  at  long  intervals;  but  where  no  water  is  commonly 
to  be  found,  even  by  digging.  This  valley,  called,  as  is  supposed,  the 
Galleta  Valley,  is  twelve  miles  wide,  and  descends  towards  the  south¬ 
east;  it  was  formerly  supposed  to  be  the  bed  of  the  Mohave  River. 

The  western  slope  of  this  valley  is  covered  with  fragments  of  basaltic 
lava,  fine-grained  and  vesicular,  together  with  obsidian,  the  fragments 
being  usually  small  and  closely  packed  together  on  a  surface  of  granitic 
sand.  Pah  Ute  Spring,  twenty  miles  from  the  Colorado,  and  the  first 
camping  ground  on  the  road,  is  at  the  foot  of  a  basaltic  ridge,  about 
200  feet  high ;  here  the  water  bursts  forth  in  a  fine  bold  stream  from 
the  junction  of  the  lava  with  the  underlying  granite.  In  this  vicinity 
is  the  first  appearance  of  stratified  rocks;  these  are  beds  inclining  in 
various  directions,  without  any  regularity,  of  a  color  varying  from  white 
to  red,  blue,  and  purple,  and  having  the  texture  and  hardness  of  burnt 
pottery  or  brick,  and  without  a  trace  of  organic  remains,  so  far  as  could 
be  ascertained.  The  age  of  these  rocks  is  not  known ;  Dr.  Cooper  con¬ 
siders  them  to  be  volcanic  materials  stratified  by  being  ejected  into 
water. 

From  this  spring,  there  is  a  steep  ascent  of  about  500  feet  to  the  sum¬ 
mit  of  the  basaltic  ridge,  and  a  descent  of  150  feet  on  the  western  side, 
and  then  the  road  rises  by  a  hardly  perceptible  grade,  over  a  sloping 
plain  of  soft  volcanic  detritus,  to  Rock  Springs,  near  the  summit  of  the 
Providence  Mountains.  This  slope  is  covered  with  quite  a  good  soil, 
derived  from  the  decomposition  of  the  volcanic  rocks,  which  produces 
considerable  forage  and  a  variety  of  vegetation,  but  which  is  almost 
destitute  of  water.  The  ascent,  although  stated  by  Lieutenant  Whip¬ 
ple  to  be  about  2500  feet  in  twenty  miles,  appears  so  slight,  that  the 
country  looks  like  a  great  level  plain,  the  rise  of  120  feet  to  the  mile 
being  lost  to  the  eye,  in  contrast  with  the  steepness  of  the  surrounding 
mountains.  Towards  the  higher  part  of  the  plain,  extensive  groves  of 
the  tree  Yucca  (Y.  baccata)  give  it  a  wooded  appearance.  A  view 
from  a  photograph  taken  at  Rock  Springs,  by  Mr.  LTIeureux,  is  given 
here,  to  illustrate  the  character  of  the  scenery  in  this  part  of  the  State. 
(See  Fig.  80.) 

At  Rock  Springs,  the  second  watering-place,  the  rock  is  granite,  form- 


the 


GREAT 


BASIN 


465 


ing  a  high  mountain  to  the  left  of  the  road,  while  on  the  right  there  is 
another,  equally  high,  of  volcanic  rocks,  in  which  layers  of  basalt  alter- 


Fig.  80. 


MACEDONIAN  VALLEY  AND  MOUNTAINS,  FROM  ROCK  SPRINGS. 


nate  with  beds  of  a  softer  material,  like  that  of  the  supposed  volcanic 
strata  at  Pah  Ute  Spring;  these  rocks  are  eroded  by  the  action  of  water 
so  as  to  form  steep  cliffs  several  hundred  feet  high.  Caves,  channels, 
and  rounded  boulders  of  granite  indicate  that  currents  of  water  once 
swept  over  nearly  all  this  range  of  mountains,  to  a  height  of  5000  feet 
above  the  sea  ;  while  the  crests  of  the  ridges,  rising  1000  feet  higher, 
with  much  sharper  outlines,  indicate  that  the  erosive  action  did  not  ex¬ 
tend  to  the  summits  of  the  ranges.  The  effects  thus  produced  are  such 
as  we  now  see  on  the  shores  of  the  ocean,  and  the  fresh  appearance 
of  the  worn  surfaces  is  remarkable. 

From  Rock  Springs  to  Chico  Spring  is  three  miles,  and  the  ascent  is 
steeper,  the  spring  being  at  the  very  summit  of  the  route,  but  sur- 


GEOL.  VOL.  I. — 59 


466 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


rounded  by  higher  points.  Many  plants  were  found  still  blooming  here 
which  had  been  in  flower  two  months  earlier  at  Fort  Mohave,  and  which 
were  now  entirely  dried  up  at  that  locality.  At  this  elevation  the  effect 
of  a  more  abundant  supply  of  moisture  was  recognized  in  the  charac¬ 
ter  of  the  vegetation.  Of  the  more  important  plants,  the  small  nut- 
pine  (P.  edulis ),  and  the  Western  juniper  (J.  occidentalis ),  were  quite 
abundant  on  the  higher  granite  mountains  each  side  of  the  road,  and 
there  was  a  belt  of  pretty  good  grass  for  a  width  of  about  thirty  miles. 
Among  the  plants  collected  here  by  I)r.  Cooper  was  the  well-known 
buffalo  grass  of  the  Great  Plains;  but  this  was  rare,  and  only  found 
near  the  summit. 

From  the  camp  at  Chico  Spring,  the  road  led  for  twenty-two  miles 
down  the  western  slope  of  the  Providence  Mountains,  passing  “Marl 
Springs”  at  a  distance  of  sixteen  miles.  The  whole  route  was  over  a 
granitic  slope,  similar  to  that  west  of  the  Colorado  River,  equally  bar¬ 
ren,  and  producing  nearly  the  same  plants.  Rear  Marl  Springs  a  low 
range  of  foot-hills  of  granite  seems  to  act  as  a  sort  of  dam  to  the  sub¬ 
terranean  channels  on  the  west  side  of  the  mountain,  so  that  the  water 
rises  to  the  surface  in  holes  dug  to  retain  it ;  but  it  rarely  overflows. 
From  Marl  Springs  there  is  a  slight  rise,  and  then  a  gradual  descent 
for  twenty  miles,  to  Soda  Lake,  the  sink  of  the  Mohave,  which  was 
four  miles  wide  where  it  was  crossed,  a  camping  ground  with  water 
being  found  on  its  western  margin.  Granitic  rocks,  with  gravel  and 
sand,  continue  all  the  way  down  the  slope,  and  fragments  of  basalt  are 
scattered  along  the  lower  half,  evidently  derived  from  extensive  lava 
fields  which  come  down  to  the  road  on  the  rmht  hand.  Several  high 
cones  to  the  north  appeared  like  centres  of  eruption,  but  no  distinct 
craters  were  visible.  The  lake,  as  it  is  called,  was  entirely  dry,  and 
never  does  contain  water,  although,  in  very  wet  seasons,  it  is  so  muddy 
as  to  be  crossed  with  difficulty.  Its  surface  is  white,  with  an  alkaline 
crust  about  one-fourth  of  an  inch  thick. 

From  this  the  road  follows  the  course  of  the  Mohave  River  for 
twelve  miles,  and  then  enters  a  canon,  through  which  it  passes  for 
nine  more,  when  the  camping  ground  called  “the  Caves”  is  reached. 
The  first  part  of  the  route  is  over  deep  drifting  sand,  approaching  more 
nearly  in  character  to  a  perfect  desert  than  any  portion  of  the  road 


THE  GREAT  BASIN. 


467 

before  traversed.  The  Larrea  eovers  most  of  it,  and  thickets  of 
shrubby  mesquit  and  scattered  trees  of  •  the  beautiful  and  fragrant 
Chilopsis  show  the  influence  of  the  moisture  which  exists  in  the  soil  at 
the  depth  of  from  three  to  six  feet  beneath  the  surface.  In  December, 
1860,  the  Mohave  ran  in  a  small  stream  over  this  sandy  desert  nearly 
to  the  lake ;  but  this  was  an  unusual  occurrence.  Soda  Lake  is  the 
lowest  point  on  the  route  between  the  Colorado  and  Cajon  Pass,  and 
according  to  Lieutenant  Whipple  is  766  feet  above  the  Colorado  at  the 
Mohave  crossing,  and  1122  feet  above  the  sea.  Metamorphic  lime¬ 
stone,  red  granite,  and  basalt  occur  at  the  western  end  of  the  lake.  In 
the  canon  the  first  water  of  the  Mohave  was  met  with;  but  at  this  sea¬ 
son  (May)  it  was  unfit  for  drinking,  standing  in  pools  and  being  very 
alkaline.  The  walls  of  the  canon  are  generally  vertical,  about  200  feet 
high,  and  consist  of  a  metamorphic  rock  resembling  serpentine,  be¬ 
tween  the  spurs  of  which  are  heavy  beds  of  detritus,  stratified  and 
destitute  of  fossils.  The  “  Caves”  are  small,  and  have  been  excavated 
in  the  metamorphic  rock  by  the  river,  which,  as  shown  by  the  marks 
on  the  walls,  sometimes  rises  to  a  height  of  five  feet  in  the  narrowest 
part  of  the  canon. 

Immediately  beyond  this  canon,  which  cuts  through  a  low  range  of 
mountains,  the  valley  widens  out  to  a  considerable  breadth  and  changes 
its  character  entirely.  An  extensive  marsh  has  been  formed  here  by 
the  obstruction  of  the  mountains,  and  around  it  the  constant  supply  of 
moisture  supports  a  good  growth  of  grass,  small  willows,  mesquit, 
chilopsis,  and  cotton-wood.  This  is  the  second  tolerably  good  camping 
ground  in  a  distance  of  110  miles  from  the  Colorado,  the  summit  of 
Providence  Mountains  being  the  other.  Ho  water  runs  beyond  this 
point  in  the  summer,  and  here  the  first  sea-breeze  was  met,  moderating 
the  intense  heat  to  some  extent ;  up  to  this  point  the  wind  had  been 
constantly  from  the  south. 

From  this  camping  ground  the  distance  to  Fort  Cady  is  fourteen 
miles,  and  at  this  place  there  is  good  water  and  other  conveniences. 
This  fort  is  an  adobe  structure,  built  by  Major  Cady  as  a  refuge  for 
small  parties  attacked  by  the  Indians,  and  there  is  another  one  of  the 
same  kind  at  Soda  Lake.  From  Fort  Cady  the  valley  widens  out, 
improving  in  the  character  of  its  soil  and  vegetation,  although  there  is  a 


468 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


want  of  running  water  in  summer  throughout  this  distance,  wliat  does 


exist  being  in  pools  which  form  regular  camping  grounds  at  intervals 
of  from  six  to  twenty  miles,  known  as  the  “  Fish  Pond,”  “  Sugar 
Loaf,”  “  Grocery,”  “  Point  of  Pocks,”  &c. ;  west  of  these  the  water 
becomes  frequent,  and  some  attempts  at  cultivation  by  settlers  w'ere 
making  in  1861.  At  most  of  the  above-mentioned  camping  grounds, 
spurs  of  mountain  ranges  come  down  to  the  river,  namely,  at  Fort 
Cady,  “  Forks  of  roads”  (to  Salt  Lake),  Sugar  Loaf,  Point  of  Rocks, 
and  Lane’s.  At  all  of  these  the  rock  is  metamorphic,  consisting  chiefly 
of  grayish  slate,  with  veins  of  quartz  and  pyrites.  Whether  any  of 
these  veins  contain  valuable  ores  remains  to  be  investigated.  In  the 
intervals  between  the  mountain  ranges  are  extensive  level  tracts  of 


stratified  detritus,  in  which  no  fossils  have  been  discovered,  and  of 
which  it  cannot  be  stated  with  certainty  whether  they  are  of  Tertiary 
or  Post-Tertiary  age.  For  about  forty  miles  west  of  Fort  Cady  they 
seem  to  consist  of  volcanic  materials  chiefly,  and  in  one  place,  at  least, 
are  in terst ratified  with  volcanic  matter.  It  is  known  that  volcanic 
mountains  and  well -formed  craters  occur  in  the  desert  and  within  no 
great  distance  of  the  Mohave  trail  (see  Williamson’s  Report,  P.  R.  R. 
Reports,  Yol.  5,  p.  31). 

The  San  Gorgono  Pass  leads  from  the  valley  of  San  Bernardino 
between  the  grand  masses  of  the  San  Bernardino  and  San  Jacinto 
Mountains,  into  the  Coahuila  Valley,  which  connects  by  a  gradually 
descending  slope  with  the  desert  and  the  Colorado  Basin.  The  Pass 
was  explored  by  Lieutenant  Parke,  under  authority  of  Lieutenant  Wil¬ 
liamson,  in  1854.  The  elevation  of  the  pass  was  given  by  him  at  2800 
feet,  and  it  was  so  uniform  in  its  ascent  and  descent  as  to  be  pronounced 
“  the  best  pass  in  the  Coast  Ranges.”  On  the  north  of  the  pass  and 
of  the  Coahuila  Valley  is  a  grand  ridge  of  granite  mountains,  which, 
so  far  as  known,  have  never  been  explored  at  all,  and  the  same  may  be 
said  of  the  San  Jacinto  Group,  which  lies  on  the  other  side.  This 
group  embraces  nearly  a  thousand  square  miles  of  mountain  ridges, 
which  look  very  grand  and  high  as-seen  from  the  summit  of  the  Santa 
Anna  Range.  The  culminating  point  we  estimated  at  10,000  feet. 
The  mountain  range  of  San  Bernardino  appears  to  extend  in  one 
nearly  unbroken  mass  almost  to  the  Colorado  River,  coming  out  a 


THE  GREAT  RASIN. 


4  69 


little  above  Fort  Yuma.  This  range  is  probably  chiefly  granitic ;  but 
there  are  some  slates  and  other  metamorphic  rocks;  and  gold  washings, 
as  well  as  quartz-mines,  are  worked  on  the  north  side  of  San  Bernar¬ 
dino,  but  not  to  any  considerable  extent.  The  farther  one  goes  south 
on  this  range  the  more  difficult  of  exploration  it  becomes,  as  it  is  at 
last  absolutely  destitute  of  water.  Of  the  region  between  this  range 
and  the  Mohave  trail,  the  same  may  be  said  now  that  was  in  1854,  by 
Williamson  :  “I  have  never  heard  of  a  white  man  who  had  penetrated 
it.”  The  United  States  Linear  Surveyors  have  given  no  information 
about  the  topography  of  the  country ;  and,  as  the  whole  of  their  work 
in  this  region  is  of  an  excessively  mythical  character,  it  would  not  be 
safe  to  draw  any  inferences  from  the  published  Land  Office  map. 

For  information  in  regard  to  the  region  southwest  of  this  range,  or 
the  continuation  of  the  Coahuila  Valley  into  what  is  called  the  Col¬ 
orado  Desert,  reference  may  be  made  to  the  Pacific  Railroad  and  Mex¬ 
ican  Boundary  Reports. 

We  close  what  we  have  to  say  in  this  volume  of  the  geology  and 
topography  of  the  Great  Basin,  by  appending  a  few  extracts  from  the 
manuscripts  of  the  United  States  and  California  Boundary  Commission, 
which  throw  some  light  on  a  region  of  great  geological  interest,  and 
which  we  are  extremely  desirous  of  exploring  whenever  circumstances 
will  permit  us  to  do  so.  As  a  characteristic  illustration  of  the  scenery 
near  the  Colorado,  we  append  a  wood-cut  (Fig.  81)  which  is  from  a 
photograph,  by  Mr.  L’Heureux,  of  the  mountain  ranges  in  the  vicinity 
of  El  Dorado  Canon;  the  exact  locality  we  are  unable  to  state,  as  there 
is  no  map  of  that  region. 

The  following  remarks  are  taken  from  a  manuscript  report  by  Dr.  J. 
R.  U.  Owen  to  the  Commissioner  of  the  United  States  and  California 


Boundary  Survey,  dated  April  15,  1861.  It  relates  to  the  district  trav¬ 
ersed  by  the  exploring  party  sent  out  to  examine  the  region  in  the 
vicinity  of  the  boundary  line  running  from  the  initial  point  on  the 
Colorado  northwest.  The  party  intended  to  traverse  this  line  and 
reach  Lake  Bigler,  but  was  obliged  to  turn  off*  the  route  and  make 
their  way  to  Owen’s  Valley,  and  thence  to  Visalia,  in  consequence  of 
the  great  difficulties  encountered,  and  especially  the  absence  of  water. 
Dr.  Owen  says : 


470 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


“  In  crossing  the  San  Bernardino  Mountains  from  Los  Angeles,  and 
coming  into  the  country  to  the  eastward  of  that  range  and  the  Sierra 


Fig.  81. 


EL  DORADO  CANON,  NEAR  THE  COLORADO  RIVER. 


Nevada,  one  is  immediately  impressed  with  its  aspect  of  sterility  and 
drouth,  as  well  as  with  the  numerous  indications  of  its  essentially  vol¬ 
canic  character,  which  present  themselves  in  almost  every  direction  in 
the  shape  of  scoriae  and  lavas  of  almost  every  variety  and  date.  Many 
of  the  hills  which  are  scattered  about  in  its  desert  plains  appear  to  be 
nothing  more  than  masses  of  lava  or  basaltic  trap-rock  that  have  been 
forced  up  through  fissures  in  the  surface  of  the  plain,  during  subter¬ 
ranean  disturbances ;  while  others  that  have  been  formed  by  the  up¬ 
heaval  of  the  ruptured  crust  of  the  earth  show,  in  the  metamorphosed 
condition  of  the  rocks  composing  them,  unmistakable  evidences  of 
intense  igneous  action,  at  some  period  in  a  geological  sense  not  very 
remote. 

“  As  far  as  the  Colorado  this  country  still  preserves  its  volcanic 
aspect,  and  in  the  few  opportunities  which  I  had  to  examine  its  rocks 
in  situ, ,  I  recognized  only  some  of  the  older  sandstones,  and  these  were 


THE  GREAT  BASIN. 


471 


very  much  modified  by  the  immediate  vicinity  of  volcanic  products, 
which  everywhere  surrounded  them. 

“  Crossing  the  Pah  Ute  Hills  in  our  route  northwestward,  and  reach- 
ing  the  Providence  Mountains,  we  found  in  that  range  gneiss  and  gran¬ 
ite  presenting  through  the  later  formations,  just  as  I  had  observed  to 
be  the  case  in  the  same  range  to  the  southward  of  the  Los  Angeles 
road.  Leaving  this  range  and  proceeding  northwestward  across  a  low 
valley  to  the  next  range,  we  enter  a  district  in  which  limestone  is  not 
only  the  prevailing  rock,  but  appears  to  form  entire  ranges  of  lofty  and 
boldly-defined  mountains,  among  which  are  comprised  the  Kingston 
Spring,  Mountain  Spring,  and  Las  Yegas  ranges,  the  latter  extending 
farther  to  the  northward.  It  is  in  this  Mountain  Spring  Range  that 
the  Potosi  mines,  which  are  now  exciting  considerable  attention 
(1861),  are  situated,  a  few  miles  south  of  the  present  Salt  Lake  road, 
on  the  western  slope  of  the  mountain,  and  several  hundred  feet  above 
the  level  of  the  plain.” 

The  Potosi  mines  are  on  veins  of  argentiferous  galena,  of  which 
nothing  definite  has  been  ascertained,  except  that  they  have  been 
abandoned.  It  is  reported,  however,  that  there  are  numerous,  well- 
defined,  and  large  lead  veins  in  this  region  ;  but  the  locality  is  one  so 
distant  and  difficult  of  access,  that  it  seems  hardly  possible  that  mines, 
unless  extremely  rich  in  the  precious  metals,  could  be  worked  there 
with  success  at  present.  The  existence  of  an  extensive  region  of  lime¬ 
stone  formations,  as  reported  by  Hr.  Owen,  with  metalliferous  veins 
occurring  in  it,  is  a  fact  of  great  scientific  interest  at  least,  and  one  can¬ 
not  but  wish  that  it  might  be  more  fully  explored,  especially  since  this 
is  the  only  district,  so  far  as  known,  on  or  near  the  Pacific  coast,  where 
limestone  extends  over  any  considerable  region  of  country.  Mr.  Biesta, 
another  member  of  the  expedition,  reports  having  seen  fine  and  pure 
specimens  of  alabaster  and  gypsum  in  this  region. 

After  examining  the  Potosi  mines,  the  party  turned  west,  and  cross¬ 
ing  the  northern  spur  of  the  Kingston  Mountains,  called  on  the  MS. 
map  of  the  expedition  by  A.  Van  Dorn,  the  “  Damask  Mountains,” 
they  struck  the  Amargosa  River;  this  they  followed  up  for  some  dis¬ 
tance,  and  entered  the  range  of  the  same  name',  which  they  crossed  and 
descended  into  Death  Valley.  The  mountains  in  the  vicinity  of  Amar- 


47:2 


GEOLOG  Y  OF  TIIE  SIERRA  NEVADA. 


gosa  Valley,  on  the  east  side,  near  Resting  Spring,  are  described  by 
Mr.  Biesta  as  “  steep  and  utterly  barren,  and  all  its  rocky  stratifications 
in  a  perfect  mass  of  confusion.”  The  rocks  are  described  as  being 
made  up  of  limestone  beds,  fifty  to  sixty  feet  thick,  with  slate,  lava, 
and  basalt;  numerous  quartz  veins  are  also  mentioned.  As  this  is  an 
interesting  region,  and  one  of  which  nothing  definite  is  known,  we 
subjoin  all  that  Dr.  Owen  says  of  it. 

“  Crossing  the  plain  of  Potosi  and  a  spur  of  the  Kingston  Mountains 
(Resting  Spring  Mountains),  on  its  western  border,  we  next  come  to 
the  Amargosa  Range  which  here  forms  the  western  limit  of  this  lime- 
stone  district.  Looking  to  the  westward  of  this  range,  the  whole 
country  between  it  and  the  Panamint  Mountains  appears  depressed, 
and  the  different  ranges  of  hills  which  are  embraced  in  the  great  bend 
of  the  Amargosa  seem  to  rise,  as  it  were,  from  the  depression  of  a 
basin.  As  we  descend  into  this  basin  we  see  on  the  western  slope  of 
the  Amargosa  Mountains  the  schists  and  sandstones  of  an  earlier  date, 
showing  out  boldly  from  under  the  limestone  which  forms  the  crest 
and  covers  the  eastern  slope  of  the  mountains.  From  this  point  these, 
with  only  occasional  masses  of  limestone  and  conglomerate,  continue  to 
characterize  the  country  until  we  reach  Owen’s  Mountains,  where  we 
again  encounter  granite,  gneiss,  crystalline  marble,  and  other  rocks  of 
this  kind.” 

The  Amargosa  River  rises  far  to  the  north,  among  utterly  unknown 
and  unexplored  regions,  and  flows  southward,  crossing  the  boundary 
line  in  about  latitude  36°  30r,  of  course  being  like  all  other  rivers  in 
this  region,  rather  a  channel  in  which  a  river  might  run  than  one  in 
which  it  does;  in  about  latitude  35°  30r  it  makes  a  great  bend  and 
turns  and  runs  northward  for  about  thirty  miles,  and  then  enters  Death 
Valley,  which  is,  in  fact,  the  sink  of  this  river.  This  valley  is  one  of 
the  most  interesting  features  of  the  topography  of  the  State,  as  it  is 
beyond  a  doubt  depressed  below  the  level  of  the  sea,  and  the  only  area 
on  this  continent,  at  any  considerable  distance  from  the  coast,  which 
is  thus  depressed.  The  valley  is  entirely  surrounded  by  very  high 
and  precipitous  mountains,  having  the  Amargosa  Range  on  the  east, 
and  the  Panamint  Mountains  on  the  west;  it  is  said  to  be  from  eight 
to  ten  miles  in  width,  and  from  thirty-five  to  forty  miles  in  length.  It 


THE  GREAT  BASIN. 


473 


lies  in  a  direction  parallel  with  the  mountain  chains  in  this  region,  or 
about  1ST.  20°  E. — S.  20°  W.  The  formations  surrounding  Death  Val¬ 
ley  are  described  as  being  to  a  large  extent  volcanic,  obsidian  being 
noticed  in  abundance  on  the  west  slope  of  the  Amargosa.  The  whole 
aspect  of  the  valley  is  one  of  the  utmost  desolation ;  the  mountains 
surrounding  it  are  naked,  arid,  of  dark  color,  and  of  imposing  gran¬ 
deur  of  form ;  the  valley  itself  is  a  sort  of  marsh  in  the  winter,  at  least 
towards  the  centre.  It  is  covered  with  a  white  efflorescence  of  alkali, 
from  which  the  rays  of  the  sun  are  reflected  with  such  power  as  almost 
to  blind  the  eyes.  The  name,  ominous  of  evil,  is  said  to  have  origin¬ 
ated  from  the  fact  that  a  party  of  emigrants  perished  here  from  thirst 
and  starvation,  as  early  as  1849;  and  it  is  said  by  Dr.  Owen  in  his 
notes,  that  he  followed  the  marks  of  their  wagon-wheels  all  the  way 
from  Furnace  Creek,  and  that  he  camped  on  the  same  spot  they  had 
occupied  eleven  years  before,  the  remains  of  their  fires  and  the  iron 
of  their  wagons  being  perfectly  preserved  during  the  eleven  years  that 
had  elapsed  since  the  unfortunate  party  attempted  to  make  their  way 
through  this  inhospitable  region.  From  this  it  is  evident  that  but  little 
if  any  rain  had  fallen  in  this  valley  for  several  years.  Dr.  Owen  remarks 
in  his  manuscript  that  this  fact,  taken  in  connection  with  the  circum¬ 
stance  that  on  every  hand  the  traces  of  tremendous  washes,  of  appa¬ 
rently  recent  origin,  are  to  be  seen  in  the  mountains,  is  one  well  calcu¬ 
lated  to  excite  surprise. 

The  barometrical  observations  taken  in  Death  Valley  by  the  Califor¬ 
nia  and  United  States  Boundary  Commission,  and  which  are  the  only 
ones  as  yet  made  in  that  region,  are  but  few  in  number,  and,  although 
they  would  have  indicated  a  depression  of  the  valley  below  the  level  of 
the  sea  as  probable,  they  would  not  have  been  sufficient  to  make  it 
certain,  had  there  not  been  a  stationary  barometer  observed  at  the 
time,  at  no  great  distance  and  at  a  point  whose  height  was  pretty  accu¬ 
rately  known.  The  observations  were  taken  at  the  northern  end  of 
the  valley  and  at  a  distance  of  180  miles  from  the  initial  point  on  the 
Colorado  where  the  corresponding  observations  were  made  by  Lieuten¬ 
ant  Ives.  Unfortunately  only  three  observations  were  taken  in  the 
bottom  of  the  valley,  and  three  more  at  the  camp  close  by.  All  the 
observations  were  carefully  investigated  and  computed  by  Major  Wil- 

GEOL.  VOL.  I. — GO 


474 


GEOLOGY  OF  THE  SIERRA  NEVADA. 


liamson,  by  whom  also  the  barometer  used  on  this  reconnaissance 
was  by  good  luck,  examined  and  compared  with  his  own  standard 
after  the  return  of  the  party,  so  that  one  source  of  uncertainty  is  thus 
entirely  got  rid  of.  Major  Williamson,  in  an  elaborate  manuscript 
paper  which  he  has  placed  in  our  hands,  comes  to  the  final  conclusion 
that  Death  Valley  is  certainly  over  100  feet  below  the  sea-level,  and 
that  it  may  be  as  much  as  250  feet  below  it,  the  mean  of  all  the  obser¬ 
vations  giving,  as  the  approximate  result,  175  feet.  It  may  be  noticed 
that  this  depression  of  the  continent  is  in  the  same  latitude  as  the  very 
highest  elevations,  or  at  least  of  the  highest  mass  of  mountains  of 
which  we  have  any  knowledge,  in  North  America.  Only  about  sixty 
miles  due  west  from  the  north  end  of  the  valley  the  culminating  points 
of  the  Sierra  Nevada  rise  to  the  height  of  15,000  feet  above  the  sea, 
and  10,000  feet  above  the  intervening  plain  of  Owen’s  Valley. 

From  Death  Valley  to  Owen’s  Valley  the  distance  in  a  straight  line 
is  about  fifty  miles,  and  there  appear  to  be  three  parallel  ranges  of 
mountains,  running  in  a  N.  W. — S.  E.  course  through  the  region, 
with  narrow  valleys  between.  The  Panamint  Mountains  extend  for 
150  miles  or  more,  from  far  in  the  north  towards  the  sink  of  the 
Mohave,  terminating  before  crossing  the  Salt  Lake  trail ;  these  form 
the  western  border  of  Death  Valley,  and  of  their  geology  little  is  • 
known  except  that  the  rocks  are  crystalline  and  metamorphic.  The 
Coso  Mountains  lie  along  the  eastern  border  of  the  road  from  Walker’s 
Pass  to  Owen’s  Lake.  They  are  made  up  of  granite  and  gneissoidal 
rocks,  and  have  been  much  prospected  for  gold  and  silver.  In  1861 
quite  a  number  of  persons  were  established  there,  and  the  erecting  of 
mills  was  talked  of.  Nothing  seems  to  have  resulted,  however,  from 
these  attempts;  and  the  inference  is,  that  the  veins  are  not  rich  enough 
to  pay  for  working  in  a  region  so  remote  and  difficult  of  access. 


- 

) 

APPENDIX  A. 


TABULAE  STATEMENT 

OF  THE  OPERATIONS  OF  THE  PRINCIPAL  QUARTZ  MILLS  RUNNING  IN  CALIFORNIA  IN  1861. 

By  W.  ASHBURNER. 


Name  and  Locality 
of  Mill. 

Water  or  steam. 

No.  of  stamps. 

No.  of  stamps  in  each  bat¬ 
tery. 

Weight  of  each  stamp. 

No.  of  blows  per  minute. 

No.  of  inches’  fall. 

Horse  power  developed  by 
each  stamp. 

Height  of  screen  above  die. 

No.  of  tons  stamped  per 
24  hours. 

Amount  of  wood  consumed 
per  ton. 

Loss  of  mercury  per  ton. 

Cost  of  extracting  quartz 
from  the  mine. 

Yield  per  ton. 

Percentage  of  gold  in  the 

quartz  at  x8o4o°o  6ne* 

Cost  of  stamping  per  ton. 

Total  cost  of  treatment  per 

ton. 

Mariposa  Co. 

lbs. 

. 

ms. 

ins. 

tons 

cords. 

lbs. 

per  ct. 

Benton,  .... 

water 

64 

4 

550 

60 

12 

1.00 

5 

80 

0.0027 

$3  53 

$8  98 

0.00177 

$0,559 

$1  04 

Bear  Valley,  . 

steam 

8 

4 

1000 

65 

12 

1.97 

20 

0.158 

0.007 

6  00 

25  24 

0.00498 

1.618 

3  10 

Mt.  Ophir,  .... 

steam 

24 

4 

500 

56 

10 

0.71 

26 

0.176 

0.019 

6  00 

16  94 

0.00334 

1.909 

2  96 

Princeton,  .... 

steam 

12 

4 

600 

60 

14 

1.27 

5 

23 

0.118 

0.026 

5  43 

27  42 

0.00541 

1.423 

3  18 

Tuolumne  Co. 

Union, . 

water 

20 

5 

500 

60 

13 

0.98 

20 

0.031 

13  00 

50  00 

0.00987 

3.145 

3  81 

Platt, . 

steam 

10 

5 

500 

58 

13 

0.95 

81 

0.130 

0.030 

5  00 

25  36 

0.00501 

2.820 

2  83 

Lomberdo’s,  . 

water 

8 

4 

650 

58 

14 

1.33 

15 

0.016 

8  00 

20  00 

0.00395 

1.243 

1  64 

Eureka . 

water 

20 

5 

600 

65 

11 

1.08 

40 

2  33 

12  00 

0.00237 

1  03 

Confidence, 

steam 

10 

5 

480 

54 

12 

0.78 

9 

10 

0.175 

1  50 

10  00 

0.00197 

2.204 

2  29 

Telegraph,  .... 

water 

10 

5 

475 

62 

10 

8 

3  00 

30  00 

0.00593 

2  00 

Knox  &  Co.,  .  . 

water 

5 

5 

6 

6  00 

20  00 

0.00395 

1  25 

Yaney  (Dry),  .  .  . 

water 

6 

3 

800 

4 

Calaveras  Co. 

r 

Crystal  (Dry),  .  . 

steam 

12 

4 

600 

60 

10 

0.91 

6 

8 

0.500 

0.128 

1  50 

80  00 

0.01580 

3.916 

8  31 

Angels  Q.  M.  Co  , 

steam 

16 

3 

490 

50 

0.62 

10 

24 

0.130 

0.125 

2  00 

5  00 

0.00098 

1.827 

2  03 

Blue  Wing  (Dry), 

steam 

24 

8 

0 


{Table  continued. 


476 


APPENDIX  A 


• 

Name  and  Locality 
ok  Mill. 

Water  or  steam. 

No.  of  stamps. 

i 

No.  of  stamps  in  each  bat¬ 
tery. 

Weight  of  each  stamp. 

|  No.  of  blows  per  minute. 

[  No.  of  inches’  fall. 

|  Horse  power  developed  by 

each  stamp. 

Height  of  screen  above  die. 

1  No.  of  tons  stamped  per 

24  hours. 

Amount  of  wood  consumed 

per  ton. 

Loss  of  mercury  per  ton. 

Cost  of  extracting  quartz  I 

from  the  mine. 

* 

Yield  per  ton. 

- 

Percentage  of  gold  in  the 

quartz  at  qqjViJ  fine. 

Cost  of  stamping  per  ton. 

. 

Total  cost  of  treatment  per 

ton. 

Amador  Co. 

pounds. 

ins 

ins. 

tons. 

1  cords. 

lbs. 

per  ct. 

Oneida, . 

steam 

16 

4 

52 

10 

16 

0.250 

0.089 

$10  50 

0.00207 

$2,351 

$2  84 

Eureka,  .... 

steam 
&  w't’r 

40 

4 

590 

80 

10 

1.19 

6 

60 

0.066 

0.064 

$2  50 

10  25 

0.00202 

0.963 

1  32 

Badger  (Upper),  .  . 

water 

16 

4 

400 

80 

10 

0.81 

25 

0.055 

2  50 

10  25 

0.00202 

0.646 

0  67 

“  (Lower),  . 

water 

12 

4 

400 

80 

10 

0.81 

20 

0.057 

2  50 

10  25 

0.00202 

0.759 

0  78 

Herbertville  (Dry),  . 

steam 

30 

5 

500 

65 

12 

0.98 

14 

0.371 

0.114 

4  50 

20  00 

0.00395 

3.043 

4  59 

American  Q.  M.  Co., 

steam 

20 

4 

575 

70 

10 

1.01 

25 

0.160 

0.067 

2  93 

10  00 

0.00197 

1.476 

1  79 

Spring  Hill, 

steam 

31 

4  &  5 

400  &  600 

70 

10 

36 

0.144 

0.050 

2  00 

10  00 

0.00197 

1.394 

1  63 

El  Dorado  Co. 

- 

Empire  (Logtown),  . 

steam 

10 

5 

600 

60 

13 

1.18 

6 

12 

0.145 

0.054 

2  75 

10  00 

0.00197 

0.990 

1  49 

Union  (Aurum  City), 

steam 

10 

5 

450 

70 

20 

0.175 

30  00 

0.00593 

2.046 

2  05 

Tulles  (Grizzly  Flat) , 

water 

11 

5  &  6 

1000.500 

42 

5  00 

■  10  00 

0.00197 

Plumas  Co. 

• 

Eureka,  .... 

water 

28 

4 

» 

3  73 

15  45 

0.00305 

6  27 

Mammoth, 

water 

12 

4 

800 

40 

8 

0.65 

10 

0.022 

25  00 

0.00498 

* 

Sierra  Co. 

* 

Sierra  Buttes, 

water 

24 

4 

600 

50 

10 

0.76 

9 

30 

0.027 

5  87 

14  82 

0.00293 

0.633 

1  36 

Independence, 

water 

12 

4 

550 

48 

9 

0.60 

8 

10 

0.033 

■ 

5  00 

15  00 

0.00297. 

0.858 

2  90 

Nevada  Co. 

Nevada  Q.  M.  Co.,  . 

water 

12 

4 

850 

60 

12 

1.54 

3 

15 

0.198 

4  00 

17  14 

0.00338 

1.466 

2  65 

Gold  Hill . 

steam 

21 

3 

730 

52 

14 

1.34 

n 

35 

0.171 

0.044 

cust’m 

1.600 

2  30 

Massachusetts  Hill,  . 

steam 

16 

4 

1000 

55 

12 

1.67 

4 

33 

0.183 

0.024 

26  00 

70  00 

0.01382 

2  91 

Empire  No.  1, 

steam 

0.104 

0.120 

5  00 

0.00098 

1  37 

“  No.  2,  .  . 

steam 

6 

3 

900 

62 

14 

1.97 

5 

18 

0.141 

0.109 

10  00 

28  00 

0.00553 

1  66 

Orleans,  .... 

steam 

9 

3 

600 

32 

10 

0.48 

2* 

8 

0.241 

0.046 

3  00 

3  23 

Allison  Ranch, 

steam 

8 

4 

950 

55 

13 

1.71 

5 

17 

0.176 

0.023 

20  00 

50  00 

0.00987 

1.678 

j  3  60 

Lady  Franklin,  .  . 

steam 

8 

4 

950 

60 

14 

2.02 

4 

22 

0.130 

0.011 

1.279 

2  01 

Forest  Springs,  . 

water 

10 

5 

800 

60 

4 

8.76 

0.044 

15  00 

52  35 

0.01034 

1.343 

2  91 

— 

H 


* 


INDEX. 


Note. — Look  for  najmes  beginning  with  San  (S.),  or  Santa  (Sta.),  under  the  letter 

next  following  these  words. 


Actinolite,  16,  55,  88. 

Age  of  Calaveras  Big  Trees,  444. 

of  detrital  deposits  under  Table  Moun¬ 
tain,  250. 

Alabaster,  near  Potosi  Mines,  471. 

Alameda  Canon,  19,  33. 

Albany  Hill,  262. 

Alcatraz  Island,  fossil  on,  77. 

Alisos  Creek,  191. 

Allison  Ranch  Mine,  291. 

Almaden  Coal  Mine,  37,  38. 

Alps,  and  Sierra  Nevada,  the  vegetation 
of,  compared,  338. 

Alta  copper-mining  district,  362. 

copper  mine,  362. 

Altaville,  363. 

Alum  Rock,  51. 

Amador,  273. 

Amador  County,  269. 

Amador  Quartz  Minin  g  Co.,  274. 

Amargosa  River,  471. 

American  River,  canon  of,  285. 

American  Valley,  307. 

Ammoniacal  salts,  in  water,  ICO. 

Anaeapa  Islands,  185. 

Andreas  (S.),  limestone  near,  74. 

Angel’s  Camp,  261. 
mills  near,  262. 

Quartz  Mining  Company,  262. 

Animal  life  on  Sta.  Barbara  Island,  183. 
Anita  (Sta.)  Canon,  173. 

Anna  (Sta.)  Range,  175. 

Antimony,  sulphuret  of,  92,  189. 

Antisell,  Dr.,  cited,  115. 

Antonio  (S.),  Hills  of,  150. 

Antonio  (S.)  Mountain,  173. 


Antonio  (S.)  River,  145. 

Argentiferous  lodes,  near  Silver  Mountain, 
449. 

Arroyo  Grande,  139. 

Arroyo  del  Puerto,  42. 

Cretaceous  strata  near,  43. 

Arroyo  Seco,  155. 

Arsenical  pyrites,  near  Keysville,  221. 
Artesian  wells,  probable  success  of  in  Salinas 
Valley,  151. 

Ashburner,  W.,  cited,  238,  261,  271,  275, 
276,  282,  290,  291,  298,  300,  301,  305. 
Asphaltum,  114,  116,  132,  137,  139,  174. 

and  Petroleum  compared,  118. 
Auriferous  slates,  geological  age  of,  210, 
226,  234,  280. 

in  Calaveras  County,  254,  258. 
in  El  Dorado  County,  279,  283. 
in  High  Sierra,  368,  406. 
in  Nevada  County,  2.v8. 
in  northern  counties,  321. 
in  Plumas  County,  306. 
in  Sierra  County,  299. 
in  Tuolumne  County,  232. 
in  Trinity  County,  323. 
on  west  slope  of  Sierra,  212. 

Auriferous  quartz,  on  Merced  River,  230. 
Auriferous  deposits,  under  Table  Mountain, 
246. 

Auriferous  veins,  character  of,  in  Nevada 
County,  290. 
on  Mariposa  estate,  226. 

Aurum  City,  quartz  mill  at,  282. 

Aurora  Mine,  58. 

Avalanches,  433. 

Axial  line  of  California,  5. 


486 


INDEX. 


Bache,  Mount,  62,  65. 

Badger  Mine,  272. 

Bald  Hills,  320. 

Bald  Mountain,  369. 

Bailey,  Mount,  323-4. 

Barbara  (Sta.),  130. 

Barbara  (Sta.)  Island,  182. 

Barometer,  on  Mount  Shasta,  345. 

Basin,  the  Great,  461. 

Land  Office  Map  of,  fictitious,  461. 
Bass;s  Ranch,  326. 

Bay  of  San  Francisco,  topographical  map 
of  region  adjacent  to,  6. 
geology  of  region  north  of,  80. 

Bear  Mountains,  253. 

Bear  Valley,  Mariposa,  224. 

Beckworth  Pass,  305. 

Benicia,  Cretaceous  strata  near,  100. 

Benito  (S.)  River,  terraces  on,  53. 

Benton  Mill,  228. 

Bielawski,  Mount,  70. 

Big  Meadows,  370. 

Plumas  County,  310. 

Big  Oak  Flat,  237. 

Big  Trees,  near  Thomas’s  mill,  368. 
near  Crane  Flat,  407. 

Calaveras,  443. 
age  of,  444. 

Bishop’s  Creek,  458. 

Bison,  fossil  remains  of,  252. 

Bituminous  slate  formation,  117. 
Bituminous  slate  in  Monte  Diablo  Range,  56. 
on  peninsula  of  San  Francisco,  73,  74. 
at  Pioneer  Mine,  90. 
south  of  Monterey,  122-155. 
near  Monterey,  161,  165. 

Black  Butte,  314. 

Black  Mountain,  65. 

Black  Point,  Mono  Lake,  451. 

Black’s  Ranch,  406. 

Black  Rocks,  457. 

Bloody  Canon,  436. 

Blue  Lead,  295,  302. 

Blue  Wing  Mill,  260. 

Boiling  Lake,  Lassen’s  Peak,  311. 

Booker’s,  53. 

Borax,  in  Mono  Lake,  452. 

Borax  Lake,  97. 

Borax  Company,  98. 

Boulders,  volcanic,  267. 

Bower  Cave,  235. 


Branch’s,  asphaltum  near,  139. 

Brea,  174. 

Brewer,  Mount,  378. 
view  from,  380,  383. 
ascent  of,  379. 
views  of,  380,  381. 

Brewer,  W.  H.,  cited,  11,  36,  39,  40,  43,  49, 
96,  110,  124,  140,  151,  153,  186,  191,  305, 
308,  313,  315,  317,-334,  350,  356,  362,  365, 
366,  383,  391,  397,  401,  404,  414,  431,  437, 
457,  461. 

Bridal  Veil  Fall,  410. 

Broderick,  Mount,  418. 

Bruno  (S.)  Mountain,  62. 

Buckeye  Tunnel,  247. 

Buckeye  Valley,  271. 

Buenaventura  (S.),  124. 

Bull  Creek,  406. 

Bullet  Chup,  323. 

Bullion,  Mount,  225. 

Bushy  Knob,  33. 

Buttes,  near  San  Luis  Obispo,  139,  141. 
near  Downieville,  300. 

Cajalco  Mine,  181. 

Cajon  Pass,  463. 

Calaveras  Creek,  48-52. 

County,  253. 
placer  mines  of,  264. 

Calcareous  tufa,  near  Monte  Diablo,  25. 
in  San  Ramon  Valley,  25. 
at  Tuscan  Springs,  208. 
near  Aurora,  438. 
at  Mono  Lake,  452. 

Campo  Seco,  257. 

Camptonville,  299. 

Canada  de  Pala,  48,  50. 

Canon  of  King’s  River,  sublime  view  in, 
379. 

Canon  of  San  Joaquin,  400. 

Canons  of  American  River,  285. 

Canons  of  Smith’s  River,  361. 

Canons,  very  deep  in  northern  counties,  358. 
Capel  Valley,  105. 

Carboniferous  fossils,  near  Pence’s  Ranch, 

210. 

in  Genesee  Valley,  309. 
at  Bass’s  Ranch,  327. 

Carboniferous  rocks  of  California,  their 
relations  to  those  of  the  East,  328. 


INDEX. 


487 


Carlos  (S.)  Peak,  9,  57. 

Carlos  (S.)  Mine,  58. 

Carmelo  Bay,  attractions  of,  165. 

Carmelo  Mission,  154. 

Carmelo  Point,  157. 

Carpenter,  P.  P.,  134. 

Carpinteria,  125. 

Carquines,  Straits  of,  12. 

Carson  Hill,  262. 

Cascade  Range,  volcanic  peaks  of,  344. 
Casteca  Lakes,  194. 

Castle  Peak,  435. 

Castle  Range,  330. 

Catalina  (Sta.)  Island,  183. 

Cathedral  Rock,  410. 

Cathedral  Peak,  425. 

Caves  in  limestone,  235,  261. 

Caves,  Elk  Valley,  351. 

Cave  in  volcanic  rocks,  near  Hurd’s  Ranch, 
351. 

Cave  Point,  27. 

Cayeguas  Ranch,  123. 

Central  California,  map  of,  366. 

Chalk  Bluffs,  296. 

Chelone,  Mount,  159. 

Chico  Creek,  fossils  at,  209. 

Chili  Gulch,  268. 

Chisnantuck,  Mount,  66. 

Chromic  iron,  near  New  Idria,  59. 
near  Crimea  House,  233. 
in  northern  counties,  361. 

Cincinnati  Mine  (quicksilver),  89. 
Cinnabar,  near  Monte  Diablo,  24. 
at  New  Idria,  58. 
at  Picacho,  60. 

on  peninsula  of  San  Francisco,  72,  78. 

south  of  Monterey,  114. 

near  Coulterville,  230. 

near  Murphy’s,  260. 

deposits  of,  in  Pope  Valley,  91. 

with  gold,  in  Bear  Valley,  92. 

Clara  (Sta.),  of  Santa  Barbara  County,  124. 
Clark  Mine,  28. 

Clayton,  J.  E.,  cited,  429,  461. 

Clear  Lake,  96, 

Clemente  (S.)  Island,  184. 

Climate  of  California,  changes  in,  423. 
Coahuila  Valley,  468. 

Coal,  near  Martinez,  12. 
near  Monte  Diablo,  27. 
of  Bellingham  Bay,  30. 


Coal  of  Nanaimo,  30. 

in  Lone  Tree  Canon,  40. 

near  Corte  de  Madera  Ranch,  71. 

north  of  Benicia,  106. 

near  Petaluma,  107. 

in  San  Rafael  Mountains,  136. 

on  Cow  Creek,  204. 

near  Pence’s  Ranch,  211. 

near  lone  Valley,  270. 

near  Buckeye  Valley,  271. 

in  Sierra  Countv,  303. 

on  Cottonwood  Creek(  320. 

Coal  mines,  near  Monte  Diablo,  27-38. 
produce  of,  29. 
quality  of,  29. 
analyses  of,  30. 
near  Santa  Barbara,  129. 

Coast  Ranges,  definition  of,  1. 

separation  of,  from  Sierra  Nevada,  2, 
167,  317. 

difficulty  in  stud}7ing  geology  of,  5. 
south  of  Monterey  Bay,  108. 
map  of,  109. 
explorations  of,  109. 
vegetation  of,  113. 

as  seen  from  the  San  Joaquin  Plain,  367. 
Coast  Range  coal  mine,  37. 

Cobb,  Mount,  88. 

Columbia,  limestone  quarries  near,  237. 
Cone  Mountain,  345. 

Cone,  volcanic,  near  Battle  Creek,  205. 
near  Mount  Shasta,  345. 
near  Silver  Mountain,  447. 
near  Mono  Lake,  454. 

Conical  form  of  Mount  Shasta,  343. 
Coniferae,  forests  of,  near  Mount  Shasta,  335. 
Contra  Costa  Hills,  9,  11. 

Cooper,  Dr.  J.  G.,  cited,  182,  183,  184,  185, 
461,  463,  466. 

Copper  mines,  near  Campo  Seco,  257. 

near  Low  Divide,  Del  Norte  County, 
361. 

of  Del  Norte  County,  363. 

Copper  mine,  Alta,  362. 

Diamond,  362. 

Copper,  native,  at  mines  of  Del  Norte 
County,  362. 

Copperopolis,  254. 

Copper  ore,  near  Monte  Diablo,  24. 
in  Penitencia  Canon,  51. 
in  San  Gabriel  Canon,  173. 


488 


INDEX. 


Copper  ore,  in  Soledad  Pass,  196. 
at  Soulsby  Vein,  238. 
in  Calaveras  County,  254,  264,  266. 
in  Amador  County,  278. 
in  Nevada  County,  294. 
in  Genesee  Valley,  309. 
near  Waldo,  360. 
shipments  from  Alta  Mine,  363. 
shipments  of,  from  Calaveras  County, 
256-7. 

shipments  of,  from  Del  Norte  County, 
363. 

Copper,  traces  of,  near  San  Antonio,  19, 
158. 

near  Murphy’s,  260. 

Corral  Hollow,  34. 

Corte  de  Madera  Ranch,  geology  near,  71. 

Coso  Mountains,  474. 

Cotopaxi,  slope  of,  344. 

Cotter,  ascent  of  Mount  Goddard,  399. 

Cottonwood  Creek,  218,  353. 

Coyote  Creek,  course  of,  48. 

Crane  Flat,  407. 

Crescent  City,  road  to,  from  Sailor  Diggings, 
360. 

Crescent  City,  363. 

Cretaceous  fossils,  near  Martinez,  12. 
on  Bagley  Creek,  23. 
in  Curry’s  Canada,  26. 
in  Monte  Diablo  group,  35. 
near  San  Luis  Gonzaga  Ranch,  46. 
near  Benicia,  101. 
near  Fort  Tejon,  191. 
near  Texas  Flat,  203. 
on  Cow  Creek,  204. 
at  Tuscan  Springs,  207. 
at  Chico  Creek,  209. 
near  Pence’s  Ranch,  210. 
on  Cottonwood  Creek,  320. 
at  Horsetown,  321. 
near  Yreka,  352. 

Cretaceous  rocks,  near  Martinez,  11,  12. 
at  Walnut  Creek  House,  15. 
near  Redwood  Peak,  18. 
at  Sunol  Valley,  18. 
metamorphic,  near  Monte  Diablo,  22. 
unaltered,  near  Monte  Diablo,  25. 
near  Corral  Hollow,  35. 
in  Lone  Tree  Canon,  40. 
in  Hospital  Canon,  41. 
in  Arroyo  del  Puerto,  42. 


Cretaceous  rocks,  in  Orestimba  Canon,  44. 
near  San  Luis  Gonzaga  Ranch,  45. 
in  Panoche  Valley,  56. 
near  New  Almaden,  68. 
on  peninsula  of  San  Francisco,  62, 
.  76-7. 

in  Marin  County,  83,  94,  97. 

near  Benicia,  100,  101. 

near  Rockville,  103. 

in  Pelevo  Hills,  104. 

section  of,  on  Puta  Creek,  105. 

lignite  in,  106. 

near  Petaluma,  107. 

in  San  Emidio  Canon,  187-9. 

near  Canada  de  las  Uvas,  190. 

in  foot-hills  of  Sierra,  201. 

in  Texas  Flat,  202. 

on  Cow  Creek,  204. 

at  Tuscan  Springs,  206. 

at  Chico  Creek,  209. 

near  Pence’s  Ranch,  210. 

in  northern  counties,  318-24,  352-4. 

Cruikshank  &  Adams’  Mine,  28. 

Cruikshank  Mine,  362. 

Cruz,  Santa,  165. 

Cruz  (Sta.)  Island,  185. 

Cruz  (Sta.)  Range,  62. 

Crystal  Mill,  261. 

Crystal  Springs,  rocks  near,  74,  75. 

Cumberland  Mine,  29. 

Curry’s  Canada,  fossils  in,  26. 

Cuyamas  Range,  112,  135. 

Cypress  Point,  161. 

Damask  Mountains,  471. 

Dana,  Mount,  435. 

ascent  of,  recommended,  404. 

Dana,  J.  D.,  cited,  344. 

Dead  Broke,  quicksilver  mine,  89. 

Death  Valley,  472. 

Deep  Spring  Valley,  460. 

Deer  Creek  Canon,  208. 

Denver  Claim,  quicksilver,  91. 

Depression,  below  sea-level,  of  Death  Val¬ 
ley,  473. 

Destruction  River,  326. 

Detrital  deposits,  Tuolumne  County,  241 

Devil’s  Acres,  337. 

Diamond  Copper  Mine,  362. 

Diamonds,  found  near  Volcano,  276. 


INDEX. 


489 


Divide,  between  forks  of  King’s  River,  370. 
Denudation,  example  of,  at  Abby’s  Ferry, 
265. 

in  northern  counties,  358. 
of  river  canons,  244. 

Dog  Creek,  329. 

Dome  Mountain,  371. 

Domes  of  granite,  401. 

Dome-structure  of  granite,  375. 

Douglas  City,  323. 

Douglas  Flat,  259. 

Downey,  Mount,  177. 

Downieville  Buttes,  300. 

Dust  columns,  raised  by  whirlwinds,  366. 
Dykes,  false,  in  Lone  Tree  Canon,  40. 
in  Pleasant  Valley,  106. 
in  granite,  Mariposa,  226. 
in  limestone,  near  Sonora,  236. 
at  Volcano,  275. 
at  Bass’s  Ranch,  326. 
near  Yreka,  352. 
in  Illinois  Valley,  360. 
in  Rockland  District,  302. 

Dyke  Ridge,  370. 


Eagle  Point,  21. 

Earthquakes,  effects  of,  15,  137. 

Ebbett’s  Pass,  446. 

El  Capitan,  Yosemite,  410. 

El  Dorado,  Mount,  187. 

El  Dorado  County,  279. 

auriferous  detritus  of,  283. 

Elephant,  fossil,  242,  252. 

Elevation,  effects  of,  on  the  system,  341. 
Elkhorn  Peak,  103. 

Elk  Valley,  350. 

Emidio  (S.)  Canon,  187. 

Encino  Ranch,  hot  spring  near,  119. 
Engelmann,  Dr.,  cited,  348. 

Enriquita  (quicksilver)  Mine,  68. 
Enterprise  Mine,  360. 

Eocene  strata,  31,  35,  57. 

Eruptive  rocks,  near  San  Rafael,  82. 

Estero  San  Antonio,  83. 

Estrella  division  of  Coast  Ranges,  9. 
Eureka  Consol.  Mg.  Co.  (copper),  295. 
Eureka  (gold)  Mine,  Tuolumne  County,  238. 

Amador  County,  272. 
Excelsior  (quicksilver)  Mine,  92. 

Excelsior  (gold)  Mine,  240. 

geol.  vol.  I. — 62 


Fall  River,  350. 

Fan-structure  in  auriferous  slates,  286. 
Fernando  (S.)  Valley,  122. 

Fish,  fossil,  66. 

Fish  Springs,  458. 

Folded  strati,  on  Arroyo  Seco,  155. 
Folsom,  Cretaceous  rocks  near,  202. 
Forests,  on  road  to  Yrosemite,  407. 
of  High  Sierra,  371. 
near  Mount  Shasta,  334. 
of  White  and  Inyo  Mountains,  457. 
of  Yosemite  Valley,  420. 
si licified,  296. 

Fort  Cady,  467. 

Fort  Crook,  350. 

Fort  Hill,  266. 

Fort  T6jon,  193. 

Four  Creeks,  367. 

Foxin’s  Ranch,  137. 

Francisco  (S.)  Geology  of  vicinity  of,  76. 

Peninsula  of,  61. 

Francisquito  (S.)  Pass,  195. 

Fremont’s  Pass,  216. 


Gabb,  Mount,  397. 

Gabb,  W.  M.,  cited,  11,  14,  31,  35,  39,  57, 
71,  79,  121,  124,  134,  135,  171,  186,  191, 
201,  203,  210,  279,  309,  328,  459,  461. 

Gabriel  (S.)  Canon,  172. 

Gabriel  (S.)  Range,  171. 

Galena,  in  Tuolumne  County,  237-8. 
near  Volcano,  276. 
in  El  Dorado  County,  282. 
at  Silver  Mountain,  449. 

Galena,  argentiferous,  near  Monterey,  114. 
at  Arroyo  Seco,  158. 
near  Nevada, *293. 
in  Potosi  Mountains,  471. 
on  Sta.  Catalina  Island,  183. 

Galleta  Valley,  464. 

Gap  in  the  Sierra,  between  Carson  and 
Walker’s  Passes,  402. 

Gardner,  J.  T.,  cited,  365,  366,  381, 383,  396, 
405,  420,  421,  422. 

Gardner,  Mount,  392. 

Gavilan  Peak,  160. 

Gavilan  Range,  159. 

Genesee  Valley,  308. 

Geysers,  93. 

origin  of,  95. 


490 


INDEX. 


■f 


Gifford's  Ranch,  308. 

Gilson  Mill,  238. 

Glaciers,  ancient,  at  head  of  Kern  and 
King’s  Rivers,  372,  375,  377,  378. 
at  head  of  San  Joaquin,  396,  398,  401. 
near  Lake  Tenaya,  425.  * 

near  Lassen’s  Peak,  316. 
near  Mount  Dana,  435,  436. 
near  Mount  Lyell,  432. 
about  Mount  Shasta,  351. 
on  Sonora  Pass,  440,  442. 
at  Silver  Valley,  445. 
near  Silver  Mountain,  447,  448. 
at  Soda  Springs,  429. 
in  Yosemite  Valley,  422. 

Goddard,  Mount,  382. 
ascent  of,  399. 

Gold,  in  Monte  Diablo  Group,  24. 
near  Sta.  Cruz,  64,  72. 
at  Tamalpais,  81. 
near  S.  Rafael,  83. 
in  Sta.  Lucia  Range,  158. 
in  San  Gabriel  Canon,  173. 
in  San  Francisquito  CaGon,  196. 
in  Chiquito  S.  Joaquin,  403. 

Goniatite,  in  auriferous  slates,  234. 
in  Inyo  Mountains,  459. 
at  Spanish  Flat,  279. 

Gorgono  (S.)  Pass,  468. 

Granite,  near  Big  Meadows,  370. 
boulders  of,  on  lava  ridges,  442. 
at  Carmelo  Bay,  155,  158. 
of  Castle  Rock  range,  331. 
dome-structure  of,  371,  375. 
on  High  Sierra,  394. 

.  on  Kaweah  River,  389. 
on  Mariposa  Estate,  225,  227. 
junction  with  sandstone  near  Pesca- 
dero,  162. 

at  Point  Pinos,  161. 
relations  of  to  lava,  on  Silver  Moun¬ 
tain  road,  447. 
in  Sierra  Sta.  Monica,  168. 
in  San  Gabriel  Range,  172. 
in  San  Emidio  Canon,  187,  189. 
near  T6jon,  193,  195. 
on  western  slope,  215,  232,  269,  281, 
288,  323,  329,  330. 
in  Siskiyou  Range,  357,  358. 
near  Temescal,  178,  179. 
near  Tomales  Point,  84,  85. 


Granite,  on  Sonora  Pass,  439. 

at  summits  of  volcanic  cones,  455. 
on  Yosemite  trail,  406. 

Grass  V  alley,  289. 

Gray  Mountains,  326. 

Gray’s  Peak,  in  Rocky  Mts.,  348. 
Greenhorn  Creek,  356. 

Greenhorn  Mountain,  221. 

Green  Rock  Ledge,  260. 

Griswold’s  Ranch,  56. 

Grizzly  Flat,  mills  near,  282. 

Guadelupe  Largo,  138. 

Guadelupe  (quicksilver)  Mine,  69. 
Guadelupe  Ranch,  152. 

Half  Dome,  Yosemite,  415. 

Hambre,  Canada  del,  14. 

Hamilton  (quicksilver)  Mg.  Co.,  91. 
Hamilton,  Mount,  43. 
ascent  of,  50. 

Hamilton,  Mount,  Group,  9,  39. 

Hancock’s  Canon,  168. 

Happy  Camp,  358. 

Helena  (Sta.)  Mountain,  85-7. 

Hell  Hollow,  226. 

Henry,  Mount,  86. 

Herbertville  Quartz  Mg.  Co.,  273. 

Hermit  Valley,  445. 

High  Sierra,  remarks  on,  364. 

Hill’s  Ranch,  134. 

Hoar,  Mount,  125. 

Hoffmann,  C.  F.,  cited,  6,  11,  39,  87,  109, 
365,  366,  372,  376,  381,  383,  405,  431. 
Hoffmann,  Mount,  424. 

Hog-wallows,  367. 

Hollenbeck’s  Rock,  47. 

Honey  Lake  Valley,  305. 

Hood,  Mount,  height  of,  compared  with 
that  of  Mount  Shasta,  348. 

Hope  Mine,  263. 

Hospital  Canon,  41. 

Horn,  Dr.,  cited,  191,  280,  459. 

fossils  discovered  by,  459. 

Horse,  fossil,  102,  242,  251,  252,  253. 

Hot  Springs,  near  Sta.  Barbara,  128. 
in  Napa  Valley,  87. 
east  of  Clear  Lake,  95,  97,  99. 
at  Encino  Ranch,  119. 
in  Sta.  Inez  Range,  128. 
near  Lassen’s  Peak,  311,  312. 
on  Walker’s  River,  438. 


INDEX. 


491 


Hurd’s  Ranch,  Cave  near,  851. 

Hydraulic  washings,  in  Tahichipi  Valley 
217. 

in  Placer  County,  285. 
in  Nevada  County,  295. 
near  Nevada  City,  296. 
in  Sierra  County,  299. 
near  North  S.  Juan,  297. 
on  Trinity  River,  323. 

Ice,  former  thickness  of,  in  the  Sierra, 
during  the  ice  period,  442. 

Illilouette,  413. 

Inclined  strata,  near  Sta.  Monica  Canon, 

170. 

Independence  Mine,.  301. 

Indians,  favorite  resort  of,  397. 

their  last  retreat,  456. 

Indian  Valley,  310. 

Inez  (Sta.)  Range,  110,  127. 

Inyo  Mountains,  456,  459. 

mineral  indications  of,  460. 
lone  City,  copper  mines  near,  278. 
lone  Valley,  269. 
coal  near,  270. 

Iron  ore,  near  San  Antonio,  19. 
south  of  Monterey,  114. 
in  and  near  San  Emidio  Canon,  189, 
194. 

in  Soulsby  Vein,  238. 
near  lone,  270. 
at  Grizzly  Flat,  282. 
near  Auburn,  284. 
near  Murphy’s,  259. 
near  Shasta  City,  322. 

Islands  of  Southern  California,  182. 

volcanic,  in  Mono  Lake,  453. 

Italian’s  Vein,  276. 

Jacinto  (S.)  Mountain,  468. 

Jackson  Butte,  277. 

Jackson,  quartz  mines  near,  271. 

Jasper,  near  Corral  Hollow,  35. 
near  Monte  Diablo,  21,  23. 
in  Mount  Hamilton  Group,  40,  41,  46. 
near  New  Almaden,  66. 
in  Marin  County,  82. 

Joaquin  (S.),  Canon  of,  400. 

Joaquin  (S.),  plains  of,  366. 

Jolon,  148. 

Josephine  Mine,  227.  , 


Juniper  Ridge,  224. 

,  Jurassic  fossils,  in  Genesee  Valley,  308. 
on  Mariposa  Estate,  226. 
near  Spanish  Flat,  279. 
description  of,  by  F.  B.  Meek,  Appen¬ 
dix  B. 

Kaweali  River,  388. 

Kern  River,  head  of,  365. 

Kettle,  the,  374. 

Keystone  Mine,  257. 

Keysville,  219,  221. 

Kincaid  Flat,  236. 

King,  C.  R.,  cited,  224,  225,  226,  305,  308, 

.  313,  314,  317,  350,  356,  365,  366,  382,  384, 
387,  388,  390,  391,  405,  409,  410,  411,  414, 
420,  421,  422,  425,  460. 

King,  Mount,  392. 

King’s  River,  370. 

Canon  of  South  Fork  of,  391. 
region  at  head  of,  365. 

Klamath  River,  357. 

Knight’s  Valley,  88. 

Knox  &  Co.’s  Mills,  240. 

Koo-chah-bee,  454. 

Lakes,  produced  by  moraines,  437. 

at  eastern  base  of  Sierra,  4. 

Lake  (quicksilver)  Mine,  92. 

Lambert’s,  rocks  near,  74. 

Lancha  Plana  (copper)  Mine,  258. 

Lassen’s  Peak,  311. 
ascent  of,  313. 

Last  Chance  (copper)  Mine,  295. 

Leandro  (S.),  18. 

Leaves,  fossil,  in  Monte  Diablo  Group,  31, 
38,  56. 

in  peninsula  of  San  Francisco,  71. 

near  Oroville,  211. 

under  Table  Mountain,  250. 

near  lone,  270. 

at  Yankee  Jim’s,  287. 

at  Chalk  Bluffs,  296. 

at  Silver  Mountain,  449. 

Leidy,  Dr.  J.,  cited,  252. 

Leviathan  Vein,  276. 

Lexington,  rocks  near,  69 
Lick  Springs,  206. 

Liebre  Ranch-house,  195. 

Limestone,  at  Abby’s  Ferry,  265. 
at  Bass’s  Ranch,  326 


492 


INDEX. 


Limestone,  at  Bower  Cave,  406. 
in  Calaveras  County,  259. 
near  Cave  City,  260. 
in  El  Dorado  County,  281. 
near  Fort  Tejon,  193. 
in  Genesee  Valley,  328. 
in  Great  Basin,  471. 
in  granite,  on  Kaweah  Biver,  388. 
at  Kincaid  Flat,  236. 
at  Murphy’s,  259. 
in  Nevada  County,  288. 
at  Pence’s  Ranch,  209. 
placer  mines  on,  241. 
near  Sta.  Cruz,  166. 
near  Sonora,  236. 
in  Tuolumne  County,  234. 
near  Volcano,  275. 

Little  Geysers,  95. 

Livermore  Pass,  32. 

Logtown,  quartz  veins  near,  282. 

Lomberdo’s  Mill,  238. 

Lone  Tree  Canon,  40. 

Los  Angeles,  174. 

Los  Gatos  Creek,  70. 

Los  Ojitos  Ranch,  149. 

Louisiana  Claim,  238. 

Low  Divide,  361. 

Lucia,  Sierra  Sta.,  Ill,  143,  157. 
section  across,  144. 

Luis  Gonzaga  (S.)  Ranch,  Cretaceous  fos¬ 
sils  at,  45. 

Luis  Obispo  (S.),  139. 

Luis  Obispo  (S.)  Valley,  139. 

Lyell,  Mount,  431. 

Macedonian  Valley,  465. 

MacLane’s  Pass,  434. 

Magnesia,  carbonate  of,  49. 

Magnesia  minerals,  near  New  Idria,  59. 

Maine  Boy’s  Tunnel,  247. 

Mammoth  Ledge,  near  Keysville,  221. 

Mammoth  Tunnel,  266. 

Mammoth  Mountain,  401. 

Mammalian  remains,  near  Benicia,  102. 
in  Tuolumne  County,  232,  242,  250,  251. 
near  Volcano,  276. 

Man  contemporaneous  with  Mastodon,  252. 

Manganese,  oxide  of,  near  San  Francisco, 
78. 

Maps  in  preparation  by  Survey,  6,  19,  78, 
109,  155,  164,  366,  443. 


Maragua  Valley,  15. 

Marble  Valley,  281. 

Margarita  (Sta.)  Valley,  144. 

Margarita  (Sta.)  River,  176. 

Maria  (Sta.)  River,  137. 

Marin  County,  geology  of,  81. 

Mariposa  Estate,  223. 

Mariposa  County,  223. 

Mariposa  Peak,  47. 

Mariposa  Vein,  229. 

Marl  Springs,  466. 

Martinez,  geology  of  vicinity  of,  11. 
Massachusetts  Hill,  292. 

Master’s  Hill,  50. 

Mastodon,  remains  of,  102,  135,  242,  252, 
276. 

Mateo  (S.),  Section  from,  to  Spanishtown, 
74. 

Mathewson,  E.,  cited,  12. 

McAlpine’s  Lode,  231. 

McCartysville,  rocks  near,  69. 

McCloud  River,  326. 

Meadows  on  Walker’s  River,  438. 

Meek,  F.  B.,  cited,  210,  226,  308,  327. 

description  of  Jurassic  fossils,  Appen¬ 
dix  B. 

Merced  and  Tuolumne  Rivers,  head  of,  403. 
Metamorphic  action,  instances  of,  16,  22,  51, 
78,  94,  104,  138,  153,  162,  163,  355,  447. 
Metamorphic  rocks,  passim. 

Meyer’s,  363. 

Middletown,  322. 

Middle  Yuba,  Canon  of,  307. 

Miguel  (S.)  Islands,  185. 

Mill,  Allison  Ranch,  292. 

Amador  Q.  Mg.  Co.’s,  274. 

Angel’s  Q.  Mg.  Co.’s,  262. 

Badger,  273. 

Benton,  228. 

Blue  Wing,  260. 

Confidence,  239. 

Cornish,  262. 

Crystal,  261. 

Eureka,  273. 

Foster  &  Co.’s,  262. 

Independence,  301. 

Knox  &  Co.’s,  240. 

Lomberdo’s,  238. 

Mountain  Quartz,  276. 

Oneida,  271. 

Pirate,  241. 


INDEX. 


493 


Mill,  Platt,  238. 

Preston’s,  240. 

Snyder’s,  240. 

Sower’s,  239. 

Sierra  Buttes,  301. 

Spring  Hill,  274. 

Street  &  Co.’s,  239. 

Telegraph,  239. 

Union,  282. 

Yane}’’,  240. 

Mill  Vein,  264. 

Milpitas  Ranch,  rocks  near,  52. 
Mine,  Peacock  (coal),  28. 

Clark  (coal),  28,  29. 

Cumberland  (coal),  29. 

Black  Diamond  (coal),  29. 
Cruikshank  &  Adams  (coal),  29. 
Pacific  (coal),  36. 

Almaden  (coal),  37. 

New  Idria  (quicksilver),  58. 

San  Carlos  (quicksilver),  58. 
Aurora  (quicksilver),  58. 
Guadelupe  (quicksilver),  66. 
New  Almaden  (quicksilver),  68. 
Enriquita  (quicksilver),  69. 
Pioneer  (quicksilver),  90. 

Lake  (quicksilver),  92. 

Excelsior  (quicksilver),  92. 
Union  (copper),  255-6. 

Keystone  (copper),  256-7. 
Lancha  Plana  (copper),  258. 
Copper  Hill  (copper),  258. 
Newton’s  (copper),  278. 
Cosmopolitan  (copper),  309. 
Diamond  (copper),  362. 
Cruikshank  (copper),  362. 

Alta  (copper),  362. 

Enterprise  (gold),  360. 

Pine  Tree  (gold),  227. 

Josephine  (gold),  227. 

Princeton  (gold),  228. 

Soulsby  (gold),  238. 

Platt  (gold),  238. 

Eureka  (gold),  239. 

Excelsior  (gold),  240. 

Blue  Wing  (gold),  260. 
Stanislaus  (gold),  263. 

Hope  (gold),  263. 

Enterprise  (gold),  263. 

Oneida  (gold),  271. 

Eureka  (gold),  272. 


Mine,  Badger  (gold),  272. 

Herbertville  (gold),  273. 

Allison  Ranch  (gold),  291. 
Massachusetts  Hill  (gold),  292. 

Pacific  Quartz  (gold),  292. 

North  Star  (gold),  292. 

Nevada  Quartz  (gold),  293. 

Sneath,  Clay  &  Co.’s  (gold),  293. 

Sierra  Buttes  (gold),  300. 

Independence  (gold),  301. 

Potosi  (silver),  471. 

Mines,  in  Coast  Ranges,  probable  value  of, 
114. 

near  West  Point,  264. 
near  Amador,  274. 
near  Volcano,  275. 
in  El  Dorado  County,  282. 
near  Zinc  House,  294. 

Miocene  fossils,  near  New  Idria,  57. 
near  Lambert’s,  72. 
at  Pigeon  Point,  73 
near  Spanish  Town,  75. 
on  Najohui  Ranch,  135. 
on  Nascimiento  River,  146. 
near  Monterey,  154. 
in  Sta.  Monica  Range,  171. 
in  Sta.  Anna  Range,  176. 
in  foot-hills  of  Sierra,  201. 

Miocene  rocks,  north  of  Monte  Diablo,  31. 
in  Sta.  Cruz  Range,  63. 
on  the  peninsula  of  S.  Francisco,  71-75. 
in  Marin  County,  84. 
in  Sta.  Susanna  Range,  121. 
in  San  Fernando  Valley,  122. 
in  Sta.  Inez  Chain,  127. 
in  Palo  Scrito  Hills,  158. 
in  Gavilan  Range,  160. 
near  Monterey  Bay,  162. 
near  Los  Angeles,  173. 
near  S.  Emidio  Canon,  188. 

Missions  in  Southern  California,  112. 
Mission  Soledad,  151. 

Mission  Carmelo,  154. 

Mitchell’s  Canon,  24. 

Mohave  Trail,  Dr.  Cooper’s  notes  on,  463. 
Mokelumne  Hill,  266. 

Mokelumne  River,  head  of,  443. 

Monica  (Sta.),  119. 

Monica  (Sta.)  Canon,  169. 

Monica  (Sta.)  Range,  110,  168. 

Mono  Lake,  450. 


494 


INDEX. 


M  ono  Lake,  former  extension  of,  45*2. 

Mono  Pass,  433. 

Monte  Diablo,  geology  of,  21. 
map  of,  19. 
view  from,  20. 
coal  near,  27. 

Monte  Diablo  Range,  description  of,  8. 
height  of  passes  and  peaks,  10. 
order  of  explorations  in,  10. 
south  of  Pacheco’s  Pass,  52. 

Monterey,  Bay  of,  160. 

Monterey,  map  of  vicinity  of,  164. 

Moore,  G.  E.,  analysis  of  Borax  Lake  water, 
98,  99. 

Moraines,  on  King’s  River,  378-9. 
in  Yosemite  Valley,  422. 
near  Soda  Springs,  429. 
around  Mount  Dana,  437. 

Morgan  Claim,  263. 

Moro  Rock,  141. 

Mountain  Spring  Range,  471. 

Mount  Opliir,  225. 

Mount  Ophir  Vein,  229. 

Mountain  Quartz  Vein,  276. 

Murphy’s,  259. 

Mvers  &  Easton  Vein,  264. 

Najohui  Ranch,  135. 

Napa  Springs,  87. 

Napa  Valley,  85. 

Nascimiento  River,  145. 

Natividad  Ranch,  160. 

Nelson’s  Point,  307. 

Nevada  Quartz  Mg.  Co.,  293. 

Nevada  County,  287. 

Nevada  Fall,  418. 

Nevadite,  315,  449. 

New  Almaden  Mine,  68. 

Newberry,  Dr.  J.  S.,  cited,  250. 

New  Idria  Mine,  58. 

Newton’s  Copper  Mine,  278. 

New  Year’s  Point,  73. 

Nicolas  (S.)  Island,  184. 

Nipoma  Ranch,  138. 

North  Dome,  Yosemite,  417. 

North  San  Juan,  297. 

North  Star  Mining  Co.,  292. 

Oakland,  geology  near,  16. 

Obelisk  Group,  425. 


Oil  from  asphaltum,  175. 

Oil  wells  near  San  Pablo,  13. 

Ojo  de  Agua  de  la  Coche,  49. 

Ojitos  (Los)  Ranch,  149. 

Oneida  Mine,  271. 

Orestimba  Canon,  44. 

Oso,  Mount,  41. 

Osos,  Canada  de  los,  141. 

Owen,  Dr.  J.  R.  N.,  cited,  469,  472,  473. 
Owen’s  River,  457. 

Owen’s  Valley,  455. 

mountains  east  side  of,  456. 
route  of  our  party  up,  457. 

Oysters,  fossil,  gigantic,  38,  72,  140. 

Oyster  beds  near  Benicia,  102. 

Pablo  (S.)  Creek,  12. 

Pablo  (S.),  metamorphic  rocks  near,  16. 
Pacheco’s  Pass,  45. 

Pacheco’s  Peak,  47. 

Pacific  Quartz  Mg.  Co.,  292. 

Pacific  Mine,  coal  (section),  36. 

Pah  Ute  Spring,  464. 

Pah  Ute  Range,  463. 

Pah  Ute  Monument,  459. 

Pajaro  River,  159. 

Palisades,  the,  393. 

Palo  Scrito  Hills,  152. 

Panoche  division  of  Coast  Ranges,  9. 
Panoche  Plain,  55. 

Panoche  Grande,  367. 

Panamint  Mountains,  472. 

Parry,  C.  C.,  cited,  348. 

Paso  el  Roble,  145. 

Pass,  highest  of  the  Sierra,  396. 

Peacock  coal  mine,  28. 

Peaks  in  Rocky  Mountains,  probable  eleva¬ 
tion  of,  349. 

Pelevo  Hills,  104. 

Penon  Blanco,  231. 

Pence’s  Ranch,  209. 

Penitencia  Creek  and  Canon,  51. 

Penitencia  Creek,  48. 

Pescadero  Ranch,  163. 

Petaluma,  82. 

geology  near,  107. 

Petroleum  excitement,  115. 

Petroleum,  flowing  wells  of,  probability  of 
finding  them,  116. 
mode  of  occurrence  of,  117. 


INDEX. 


495 


Petroleum  swindling  companies,  115. 

Picacho,  cinnabar  near,  60. 

Pigeon  Point,  rocks  at,  73. 

Photographs  of  Yosemite,  408. 

Pilgrim  Camp,  351. 

Pilot  Peak,  306. 

Pine  Tree  Mine,  227. 

Pine  Mountain,  88. 

Pinos,  Mount,  187,  194. 

Pioneer  quicksilver  claim,  90. 

Pike’s  Peak,  348. 

Pitt,  Mount,  355. 

Pittsburg  quicksilver  claim,  90. 

Placer  County,  283. 

Placers,  in  Klamath  River,  357. 

Placer  mines,  in  Tuolumne  County,  241. 
on  western  slope  of  Sierra,  in  northern 
counties,  321-3,  326,  330,  356,  359, 
360. 

on  Bull  Creek,  406. 

near  Sonora,  443. 

in  San  Bernardino  Range,  469. 

Plants,  fossil,  on  Cottonwood  Creek,  353. 

Platt  Mine, *238. 

Pleasant  Valley,  106. 

Pliocene,  fossils  of,  near  Kirker’s  Pass,  32. 
near  Livermore’s  Pass,  38. 
near  San  Francisco,  79. 
near  Cayeguas  Ranch,  124. 
at  Sta.  Barbara,  134. 
at  Atascadero  Ranch,  144. 
under  Table  Mountain,  250,  251. 

Pliocene  strata,  near  San  Francisco,  79. 
in  Pleasant  Valley,  106. 
in  Sta  Susanna  Range,  121,  122. 
at  Pence’s  Ranch,  211. 
near  lone,  270. 

Plumas  Countv,  304. 

Pluto’s  Cave,  351. 

Point  San  Pedro,  rocks  near,  76. 

Pope  Valley,  quicksilver  mines  in,  91. 

Porcupine  Flat,  424. 

Porphyry,  near  Temescal,  179. 

Portuguese  Flat,  330. 

Post-Pliocene  deposits,  near  San  Pablo,  13. 
near  Kirker’s  Pass,  32. 
at  Booker’s,  54. 
near  Merced  Lake,  79.  , 
near  Benicia,  102. 
about  Sta.  Barbara,  132,  137. 
on  Sta.  Barbara  Island,  183. 


Post-Pliocene  fauna,  252. 

Post-Tertiary  detritus,  elevated  at  Booker’s, 
53. 

Post-Tertiary  near  Benicia,  102. 

in  San  Emidio  Canon,  187. 

Pratt’s  Hill,  269. 

Princeton  vein,  228. 

Process  for  saving  gold,  294. 

Providence  Mountains,  464. 

Punta  de  los  Reyes,  85. 

Puta  Creek,  105. 

Quartz  Mining,  in  Mariposa  County,  227. 
in  Tuolumne  County,  237. 
in  Calaveras  County,  261. 
in  Amador  County,  271. 
in  El  Dorado  County,  282. 
in  Placer  County,  285. 
in  Nevada  County,  289. 
in  Sierra  County,  300. 
in  Siskiyou  Range,  359. 
in  San  Bernardino  Range,  469. 

Quartz  Vein,  the  Great,  230,  239,  261,  262. 
Quicksilver,  geological  position  of  its  ores, 
68. 

production  of,  at  New  Almaden,  68. 
exports  of,  from  California,  69. 
mines  of,  in  Napa  County,  89. 
native,  at  Pioneer  Mines,  89,  90. 
prospecting  for,  at  Corte  de  Madera 
Ranch,  71. 

Quicksilver  rock,  16,  19,  83,  89. 

Rafael  (S.),  geology  near,  82. 

Rafael  (S.)  Range,  112,  135. 

Rag  Canon,  105. 

Railroad  Flat,  266. 

Ramon  (S.)  River,  14. 

Valley,  15. 

Rathgeber  Vein,  264. 

Red  Bluff,  319. 

Red  Bluffs,  Mount  Shasta,  339. 

Red  Dog,  hydraulic  washings  near,  296. 

Red  snow,  on  Mount  Shasta,  338. 

Redwood  groves,  near  Sta.  Cruz,  64. 
Redwood  Peak,  18. 

Reed  Lode,  255. 

Reeve’s  Ranch,  357. 

liemond,  A.,  cited,  79,  101,  106,  234,  269, 
275,  317,  346. 


496 


INDEX. 


Resting  Spring  Mountain,  472. 

Rhinoceros,  remains  of,  251,  268. 

Rhyolite,  315. 

Rincon,  Canada  del,  166. 

Ritchie’s  Station,  445. 

Robinson’s  Ranch,  156. 

Rockland  cupriferous  district,  362. 

Rock  Springs,  Mohave  trail,  464. 
Rockville,  103. 

Rocky  Mound,  16. 

Rocky  Mountains,  height  of  peaks  in,  348. 
Rodeo  Valley,  12. 

Rosa  (Sta.)  Island,  185. 

Round  Valley,  Owen’s  Valley,  458. 

Ruby  Claim,  362. 

Ruined  City,  near  Sta.  Cruz,  63. 


Sacramento  Valley,  319. 

Salinas  Valley,  109,  145,  150. 

Sailor  Diggings,  359. 

Salmon  Mountains,  356. 

Salt,  near  Canada  de  las  Uvas,  186. 

west  of  Owen’s  Valley,  460. 

Sand,  for  glass,  161. 

Sandstone,  for  architectural  purposes,  202. 
Sciad  Valley,  357. 

Scorpion  Hills,  120. 

Scott’s  Bar,  356. 

Scott  Valley,  356. 

Sea  of  Ice,  in  San  Joaquin  Valley,  401. 
Searsville,  geology  near,  71. 

Sections,  geological,  described  and  figured, 
14,  36,  37,  106,  121,  123,  128,  129,  130, 
132,  134,  135,  138,  141,  144,  147,  149,  157, 
162,  170,  189,  203,  207,  211,  247,  248,354. 
Sections  across  Yosemite  Valley,  409,  416. 
Sentinel  Dome,  412. 

Sentinel  Rock,  412. 

Serpentine,  in  Contra  Costa  Hills,  19. 
in  Monte  Diablo  Group,  22,  24,  59. 
in  Mount  Hamilton  Group,  49. 
near  San  Francisco,  67,  74,  78. 
north  of  San  Francisco  Bay,  82,  83,  86, 
88,  90,  92,  93,  105. 

south  of  Monterey  Bay,  136,  142,  143, 
149,  160. 

in  Mariposa  County,  225. 
in  Tuolumne  County,  233. 
in  Calaveras  County,  256. 
in  Placer  County,  284,  285. 


Serpentine,  in  Plumas  County,  306. 

on  western  slope,  northern  counties, 
359,  360,  361,  363. 

Shasta  City,  322. 

Shasta,  Mount,  view  of  from  Soda  Springs, 
332. 

ascent  of,  333. 

forests  near,  334. 

view  from,  341. 

regular  conical  form  of,  343. 

determination  of  height  of,  345. 

view  of,  from  Elk  Valley,  350. 

view  of,  from  N.  E.  side,  351. 

Shasta  Valley,  352. 

‘  Sheep  on  Sta.  Barbara  Island,  185. 

Sheep  Rock,  390. 

Sheldon,  H.  H.,  cited,  257,  293. 

Sierra  County,  298. 

Sierra  Buttes  Quartz  Mining  Co  ,  300. 

Sierra  Nevada,  remarks  on,  2,  4,  317,  364. 
appearance  of,  from  Owen’s  Valley,  456. 

Sierra,  the  High,  364. 
explorations  in,  365. 

Silliman,  Mount,  376. 

Silver  mines,  at  Arroyo  Seco,  158. 
in  Coast  Ranges,  114. 
in  San  Gabriel  Canon,  173. 
near  San  Emidio  Canon,  194. 
about  Genesee  Valley,  309. 
at  Silver  Mountain,  449. 

Silver  Mountain  Peak,  448. 

Siskiyou  Mountains,  355,  361. 

Sisson,  J.  H.,  guide,  332. 

Size  of  Big  Trees,  444. 

Slates,  auriferous,  on  Mariposa  Estate,  225. 
on  Cottonwood  Creek,  353. 
west  of  Yreka,  356. 
on  Klamath  River,  359. 
near  Waldo,  359. 
in  Del  Norte  County,  361. 
near  Crescent  City,  363. 
nearly  unaltered,  Upper  Sacramento 
Valley,  329. 

Slate  Creek,  330. 

Slates  at  summit  of  the  Sierra,  396. 

Slates,  metamorphic  ;  see  Geology  of  Sierra 
Nevada,  passim. 

\  Slate  Peaks,  397. 

Sfate  Range,  221. 

Slopes  of  mountains,  exaggerated  by  travel¬ 
lers  and  artists,  344. 


INDEX. 


497 


Sneath,  Clay  &  Co.’s  Mill,  293. 

Soda  Lake,  466. 

Soda  Springs,  near  Mount  Shasta,  331. 
Soda  Springs,  on  Mono  trail,  427-8. 
Soledad,  mission  of,  151. 

Soledad  Pass,  195. 

Solfatara,  on  Mount  Shasta,  340. 

Sonora  Pass,  437. 

South  Dome,  Yosemite,  419. 

Sowers’  Mill,  239. 

Soulsby  Vein,  238. 

Soulsbyville,  238.  253. 

Spanishtown,  75. 

Spring  Hill  Mills,  274. 

Springs,  Tuscan,  208. 

mineral,  at  Alum  Rock,  51. 
on  Upper  Sacramento  River,  331. 
in  volcanic  regions,  350. 

Stanislaus  River,  243. 

head  of,  440. 

Steamboat  Spring,  311. 

Stone’s  Ferry,  329. 

Strawberry  Flat,  332. 

Sugar  Loaf,  296. 

Sugar  Loaf  Rock,  377. 

Sugar  Pine  Mining  District,  240,  442. 
Sugar  Pine,  size  of,  336. 

Suisun  Marble,  104. 

Sulphur,  near  Borax  Lake,  99. 

on  San  Buenaventura  River,  125. 
at  Boiling  Lake,  312. 

Sulphur  Banks,  94,  99. 

Sulphur  Peak,  93. 

Summit  of  Mount  Shasta,  character  of,  337. 
Suhol  Valley,  18. 

Susanna  (Sta.) 'Range,  110,  120. 

Sweetbrier  Ranch,  330. 

Table  Mountain,  Marin  County,  81. 

Tuolumne  County,  243. 

Tahiehipi  Valley,  216. 

Tamalpais,  81. 

Tapir,  fossil,  252. 

Tar  Springs,  near  Los  Angeles,  174. 

T6jon  Pass,  192. 

Reservation,  191. 

Telegraph  Mill,  239. 

Tellurides  of  Silver,  263. 

Temescal  Range,  178. 

Tenaya,  Lake,  425. 


Terraces  in  Monte  Diablo  Range,  53,  54,  56. 
at  Pigeon  Point,  73. 
south  of  Monterey  Bay,  147,  150,  151, 
165. 

in  Santa  Monica  Canon,  169. 
on  San  Nicolas  and  San  Clemente 
Islands,  184. 
on  Walker’s  River,  438. 
around  Mono  Lake,  451. 
i  Tertiary  deposits,  in  Contra  Costa  Hill', 
12,  14,  15. 

in  Monte  Diablo  Group,  27,  31,  33,  35, 
38. 

in  Mount  Hamilton  Group,  44.  50. 
in  Monte  Diablo  Range,  52,  56,  57. 
on  peninsula  of  San  Francisco,  62,  67, 
69,  70,  79. 

north  of  San  Francisco  Bay,  82,  102, 
103. 

south  of  Los  Angeles,  167,  170,  173. 
near  Canada  de  las  Uvas,  187,  188,  191, 
194. 

in  foot-hills  of  Sierra,  201,  211. 
on  west  slope  of  Sierra.  269,  271,  303. 
Texas  Flat,  202,  242. 

Thomas’s  Mill,  368. 

Three  Brothers,  Yosemite,  411. 

Three  Devils,  357. 

Thurston’s  Lake,  97. 

Tin,  in  Temescal  Range,  181. 

near  Weaverville,  181. 

Todd’s  Valley,  287. 

Tomales  Bay,  83. 

Topography  of  California,  simplicity  of,  3. 
Tower  Rocks,  near  Monte  Diablo,  27. 

Trap  dykes  in  limestones,  326. 

Trask,  Dr.  J.  B.,  cited,  202,  203,  280,  327. 
Tres  Pinos,  53. 

Triassic  fossils  near  Gilford’s  Ranch,  280, 
309. 

near  Spanish  Flat,  279. 

Triassic  rocks,  in  Inyo  Mountains,  459. 
Trinity  Mountains,  323,  331. 

Trinity  River,  fossils  in,  324. 

:  Triunfo  Ranch,  123. 

Tufa,  calcareous,  near  Monte  Diablo,  25. 

at  Texas  Flat,  242. 

Tulare  Valley,  187. 

south  end  of,  192. 

Tul6  River,  222. 

Tunnels  in  Table  Mountain,  248. 


GEOL.  VOL.  I. — 63 


498 


INDEX. 


Tuolumne  County,  232. 

River,  426. 

Valley,  Upper,  visit  to,  recommended, 
404. 

Tuscan  Springs,  206. 

section  at,  207. 

Tuttletown,  mills  near,  239. 

Tutucanula,  410. 

Twin  Sisters,  104. 

Tyndall,  Mount,  382. 
ascent  of,  384. 
view  from,  386. 

Unaltered  strata  at  base  of  Sierra  Nevada, 
199,  329. 

Unicorn  Peak,  427. 

Union  Mine,  256. 

Upheaval,  systems  of,  in  southern  Coast 
Ranges,  110. 

Upper  Tuolumne  Valley,  427. 

Uvas,  Canada  de  las,  190. 

Vacca  Mountains,  104. 

Vallejo,  rocks  near,  102. 

Van  Dorn’s  map,  462. 

Veatch,  Dr.  J.  A.,  cited,  98,  99,  207. 
Vegetation  at  hot  springs,  96. 
near  Tejon,  197. 

Vein,  great  quartz,  in  Tuolumne  County, 
237. 

Vernal  Fall,  418. 

Volcanic  deposits,  in  Monte  Diablo  Group, 
32. 

in  Mount  Hamilton  Group,  47. 
at  and  about  Mt.  St.  Helena,  86,  87,  95, 
100,  103,  104. 
near  Sonoma,  107. 
on  Sta.  Catalina  Island,  183. 
near  T6jon,  191,  195. 
in  foot-hills  of  Sierra,  205,  208. 
on  western  slope  of  Sierra,  214,  232, 
241,  244,  253,  254,  258,  265,  266,  277, 
278,  283,  286,  296,  299,  301,  306,  307, 
310,  314,  317,  319,330,  344,  350. 
in  High  Sierra,  397,  400,  439,  441,  445, 
446,  449,  453,  454,  458,  460,  468. 
Volcanic  action,  instances  of,  95,  97,  174, 
315,  340,  448,  453. 

Volcano,  275. 

quartz  mine  near,  275. 

Wackenreuder’s  topographical  work,  288, 
443. 


Waldo,  359. 

Walker’s  Basin,  218. 

Walker’s  Pass,  220. 

Walnut  Creek,  geology  of  region  near,  13. 
Warm  Springs,  Owen’s  Valley,  458. 
Washes  from  the  Sierra,  457. 

!  Water-falls,  Bridal  Veil,  410. 

Yosemite,  413. 

Vernal  and  Nevada,  418. 

Water  of  Mono  Lake,  452. 

Watkins,  C.  E.,  photographs  of  Yosemite, 
408. 

Waugh’s  Ferry,  325,  326. 

Well  Lode,  294. 

West  Point,  264. 

Whale,  bones  of,  137. 

J  White  Mountains,  387,  456. 

White  Mountain  peaks,  probable  height  of, 
460. 

White  River,  201. 

Whitman  Vein,  275. 

I  Whitney,  Mount,  382. 
ascent  of,  390. 

Williamson,  Major,  U.  S.  E.,  cited,  195, 
217,  347,  382,  473,  474. 

Williamson,  Mount,  382,  386. 

Wilson’s  Ranch,  fossil  oysters  near,  140. 
Wood,  fossil,  in  Monte  Diablo  Group,  31,  38. 
under  Table  Mountain,  249. 
in  Calaveras  County,  265. 
in  Placer  County,  287. 
in  Nevada  County,  296,  297. 
in  northern  counties,  320,  353. 

Wooden  Valley,  105. 

Wosnessensky,  86. 

Yalloballey,  325. 

Yaney  Mill,  240. 

Yankee  Jim’s,  287. 

Yreka,  scenery  on  road  to,  325. 

roads  to,  from  Shasta  City,  325. 
Yosemite  Fall,  413. 

Yosemite  Valley,  description  of,  407. 

Gardner  and  King’s  map  of,  405,  421 
origin  of,  421. 
photographs  of,  408. 
sections  across,  409,  416. 

Zinc,  sulphuret  of,  238,  282. 

Zinc  House,  copper  ores  near,  294. 


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